From a3bfdc8858dfd89ebc7d154e62da45a6ddbdebd3 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Fri, 25 Sep 2020 14:20:15 -0700
Subject: [PATCH 01/11] add Account class and tests

---
 CHANGELOG.md                              |  23 +-
 README.md                                 |   1 +
 docs/README.md                            |   1 +
 docs/classes/_account_.account.md         | 167 +++++++++++
 docs/interfaces/_account_.accountdata.md  |  48 ++++
 docs/modules/__types_ethjs_util_index_.md |   5 +
 docs/modules/_account_.md                 |  36 ++-
 docs/modules/_externals_.md               |   1 -
 docs/modules/_hash_.md                    |  22 +-
 package.json                              |   2 +-
 src/account.ts                            | 156 +++++++++--
 src/index.ts                              |   2 +-
 test/account.spec.ts                      | 327 +++++++++++++---------
 typedoc.js                                |   6 +-
 14 files changed, 606 insertions(+), 191 deletions(-)
 create mode 100644 docs/classes/_account_.account.md
 create mode 100644 docs/interfaces/_account_.accountdata.md
 create mode 100644 docs/modules/__types_ethjs_util_index_.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b9a0e598..d4474e09 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,28 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 
 ## [7.0.6] - [UNRELEASED]
 
-[ ADD REFERENCES TO YOUR WORK HERE UPON PRs. PLEASE ADOPT THE VERSION IF YOUR PR REQUIRES. ]
+This release adds a new `Account` class intended as a modern replacement for `ethereumjs-account`. It has a shape of `Account(nonce?: BN, balance?: BN, stateRoot?: Buffer, codeHash?: Buffer)`.
+
+**Instantiation**
+
+The static factory methods assist in creating an `Account` object from varying data types: `Object: fromAccountData`, `RLP: fromRlpSerializedAccount`, and `Array: fromValuesArray`.
+
+**Methods**: `isEmpty(): boolean`, `isContract(): boolean`, `serialize(): Buffer`
+
+Example usage:
+
+```typescript
+import { Account, BN } from 'ethereumjs-util'
+
+const account = new Account(
+  new BN(0), // nonce, default: 0
+  new BN(10).pow(new BN(18)), // balance, default: 0
+  undefined, // stateRoot, default: KECCAK256_RLP (hash of RLP of null)
+  undefined, // codeHash, default: KECCAK256_NULL (hash of null)
+)
+```
+
+For more info see the documentation or examples of usage in `test/account.spec.ts`.
 
 ## [7.0.5] - 2020-09-09
 
diff --git a/README.md b/README.md
index 95733ae0..654c9561 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,7 @@ assert.equal(new BN('dead', 16).add(new BN('101010', 2)), 57047)
 ### Modules
 
 - [account](docs/modules/_account_.md)
+  - Account class
   - Private/public key and address-related functionality (creation, validation, conversion)
 - [address](docs/modules/_address_.md)
   - Address class and type
diff --git a/docs/README.md b/docs/README.md
index 9a7b907a..7dff9c06 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -6,6 +6,7 @@
 
 ### Modules
 
+* ["@types/ethjs-util/index"](modules/__types_ethjs_util_index_.md)
 * ["account"](modules/_account_.md)
 * ["address"](modules/_address_.md)
 * ["bytes"](modules/_bytes_.md)
diff --git a/docs/classes/_account_.account.md b/docs/classes/_account_.account.md
new file mode 100644
index 00000000..4f3d33d8
--- /dev/null
+++ b/docs/classes/_account_.account.md
@@ -0,0 +1,167 @@
+[ethereumjs-util](../README.md) › ["account"](../modules/_account_.md) › [Account](_account_.account.md)
+
+# Class: Account
+
+## Hierarchy
+
+* **Account**
+
+## Index
+
+### Constructors
+
+* [constructor](_account_.account.md#constructor)
+
+### Properties
+
+* [balance](_account_.account.md#balance)
+* [codeHash](_account_.account.md#codehash)
+* [nonce](_account_.account.md#nonce)
+* [stateRoot](_account_.account.md#stateroot)
+
+### Methods
+
+* [isContract](_account_.account.md#iscontract)
+* [isEmpty](_account_.account.md#isempty)
+* [serialize](_account_.account.md#serialize)
+* [fromAccountData](_account_.account.md#static-fromaccountdata)
+* [fromRlpSerializedAccount](_account_.account.md#static-fromrlpserializedaccount)
+* [fromValuesArray](_account_.account.md#static-fromvaluesarray)
+
+## Constructors
+
+###  constructor
+
+\+ **new Account**(`nonce`: BN‹›, `balance`: BN‹›, `stateRoot`: Buffer‹›, `codeHash`: Buffer‹›): *[Account](_account_.account.md)*
+
+*Defined in [account.ts:77](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L77)*
+
+This constructor takes the values, validates and assigns them.
+Use the static factory methods to assist in creating an Account from varying data types.
+
+**Parameters:**
+
+Name | Type | Default |
+------ | ------ | ------ |
+`nonce` | BN‹› | new BN(0) |
+`balance` | BN‹› | new BN(0) |
+`stateRoot` | Buffer‹› | KECCAK256_RLP |
+`codeHash` | Buffer‹› | KECCAK256_NULL |
+
+**Returns:** *[Account](_account_.account.md)*
+
+## Properties
+
+###  balance
+
+• **balance**: *BN*
+
+*Defined in [account.ts:43](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L43)*
+
+___
+
+###  codeHash
+
+• **codeHash**: *Buffer*
+
+*Defined in [account.ts:45](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L45)*
+
+___
+
+###  nonce
+
+• **nonce**: *BN*
+
+*Defined in [account.ts:42](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L42)*
+
+___
+
+###  stateRoot
+
+• **stateRoot**: *Buffer*
+
+*Defined in [account.ts:44](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L44)*
+
+## Methods
+
+###  isContract
+
+▸ **isContract**(): *boolean*
+
+*Defined in [account.ts:112](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L112)*
+
+Returns a `Boolean` deteremining if the account is a contract.
+
+**Returns:** *boolean*
+
+___
+
+###  isEmpty
+
+▸ **isEmpty**(): *boolean*
+
+*Defined in [account.ts:119](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L119)*
+
+Returns a `Boolean` determining if the account is empty.
+
+**Returns:** *boolean*
+
+___
+
+###  serialize
+
+▸ **serialize**(): *Buffer*
+
+*Defined in [account.ts:105](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L105)*
+
+Returns the RLP serialization of the account as a `Buffer`.
+
+**Returns:** *Buffer*
+
+___
+
+### `Static` fromAccountData
+
+▸ **fromAccountData**(`accountData`: [AccountData](../interfaces/_account_.accountdata.md)): *[Account](_account_.account.md)‹›*
+
+*Defined in [account.ts:47](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L47)*
+
+**Parameters:**
+
+Name | Type |
+------ | ------ |
+`accountData` | [AccountData](../interfaces/_account_.accountdata.md) |
+
+**Returns:** *[Account](_account_.account.md)‹›*
+
+___
+
+### `Static` fromRlpSerializedAccount
+
+▸ **fromRlpSerializedAccount**(`serialized`: Buffer): *[Account](_account_.account.md)‹›*
+
+*Defined in [account.ts:58](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L58)*
+
+**Parameters:**
+
+Name | Type |
+------ | ------ |
+`serialized` | Buffer |
+
+**Returns:** *[Account](_account_.account.md)‹›*
+
+___
+
+### `Static` fromValuesArray
+
+▸ **fromValuesArray**(`values`: Buffer[]): *[Account](_account_.account.md)‹›*
+
+*Defined in [account.ts:68](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L68)*
+
+**Parameters:**
+
+Name | Type |
+------ | ------ |
+`values` | Buffer[] |
+
+**Returns:** *[Account](_account_.account.md)‹›*
diff --git a/docs/interfaces/_account_.accountdata.md b/docs/interfaces/_account_.accountdata.md
new file mode 100644
index 00000000..698b49df
--- /dev/null
+++ b/docs/interfaces/_account_.accountdata.md
@@ -0,0 +1,48 @@
+[ethereumjs-util](../README.md) › ["account"](../modules/_account_.md) › [AccountData](_account_.accountdata.md)
+
+# Interface: AccountData
+
+## Hierarchy
+
+* **AccountData**
+
+## Index
+
+### Properties
+
+* [balance](_account_.accountdata.md#optional-balance)
+* [codeHash](_account_.accountdata.md#optional-codehash)
+* [nonce](_account_.accountdata.md#optional-nonce)
+* [stateRoot](_account_.accountdata.md#optional-stateroot)
+
+## Properties
+
+### `Optional` balance
+
+• **balance**? : *BNLike*
+
+*Defined in [account.ts:19](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L19)*
+
+___
+
+### `Optional` codeHash
+
+• **codeHash**? : *BufferLike*
+
+*Defined in [account.ts:21](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L21)*
+
+___
+
+### `Optional` nonce
+
+• **nonce**? : *BNLike*
+
+*Defined in [account.ts:18](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L18)*
+
+___
+
+### `Optional` stateRoot
+
+• **stateRoot**? : *BufferLike*
+
+*Defined in [account.ts:20](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L20)*
diff --git a/docs/modules/__types_ethjs_util_index_.md b/docs/modules/__types_ethjs_util_index_.md
new file mode 100644
index 00000000..45cd1a7f
--- /dev/null
+++ b/docs/modules/__types_ethjs_util_index_.md
@@ -0,0 +1,5 @@
+[ethereumjs-util](../README.md) › ["@types/ethjs-util/index"](__types_ethjs_util_index_.md)
+
+# Module: "@types/ethjs-util/index"
+
+
diff --git a/docs/modules/_account_.md b/docs/modules/_account_.md
index b7a054eb..08125b1d 100644
--- a/docs/modules/_account_.md
+++ b/docs/modules/_account_.md
@@ -4,6 +4,14 @@
 
 ## Index
 
+### Classes
+
+* [Account](../classes/_account_.account.md)
+
+### Interfaces
+
+* [AccountData](../interfaces/_account_.accountdata.md)
+
 ### Variables
 
 * [publicToAddress](_account_.md#const-publictoaddress)
@@ -30,7 +38,7 @@
 
 • **publicToAddress**: *pubToAddress* = pubToAddress
 
-*Defined in [account.ts:160](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L160)*
+*Defined in [account.ts:257](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L257)*
 
 ## Functions
 
@@ -38,7 +46,7 @@
 
 ▸ **generateAddress**(`from`: Buffer, `nonce`: Buffer): *Buffer*
 
-*Defined in [account.ts:82](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L82)*
+*Defined in [account.ts:179](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L179)*
 
 Generates an address of a newly created contract.
 
@@ -57,7 +65,7 @@ ___
 
 ▸ **generateAddress2**(`from`: Buffer, `salt`: Buffer, `initCode`: Buffer): *Buffer*
 
-*Defined in [account.ts:103](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L103)*
+*Defined in [account.ts:200](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L200)*
 
 Generates an address for a contract created using CREATE2.
 
@@ -77,7 +85,7 @@ ___
 
 ▸ **importPublic**(`publicKey`: Buffer): *Buffer*
 
-*Defined in [account.ts:183](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L183)*
+*Defined in [account.ts:280](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L280)*
 
 Converts a public key to the Ethereum format.
 
@@ -95,7 +103,7 @@ ___
 
 ▸ **isValidAddress**(`hexAddress`: string): *boolean*
 
-*Defined in [account.ts:21](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L21)*
+*Defined in [account.ts:127](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L127)*
 
 Checks if the address is a valid. Accepts checksummed addresses too.
 
@@ -113,7 +121,7 @@ ___
 
 ▸ **isValidChecksumAddress**(`hexAddress`: string, `eip1191ChainId?`: undefined | number): *boolean*
 
-*Defined in [account.ts:70](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L70)*
+*Defined in [account.ts:167](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L167)*
 
 Checks if the address is a valid checksummed address.
 
@@ -134,7 +142,7 @@ ___
 
 ▸ **isValidPrivate**(`privateKey`: Buffer): *boolean*
 
-*Defined in [account.ts:121](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L121)*
+*Defined in [account.ts:218](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L218)*
 
 Checks if the private key satisfies the rules of the curve secp256k1.
 
@@ -152,7 +160,7 @@ ___
 
 ▸ **isValidPublic**(`publicKey`: Buffer, `sanitize`: boolean): *boolean*
 
-*Defined in [account.ts:131](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L131)*
+*Defined in [account.ts:228](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L228)*
 
 Checks if the public key satisfies the rules of the curve secp256k1
 and the requirements of Ethereum.
@@ -172,7 +180,7 @@ ___
 
 ▸ **isZeroAddress**(`hexAddress`: string): *boolean*
 
-*Defined in [account.ts:29](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L29)*
+*Defined in [account.ts:300](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L300)*
 
 Checks if a given address is a zero address.
 
@@ -190,7 +198,7 @@ ___
 
 ▸ **privateToAddress**(`privateKey`: Buffer): *Buffer*
 
-*Defined in [account.ts:166](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L166)*
+*Defined in [account.ts:263](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L263)*
 
 Returns the ethereum address of a given private key.
 
@@ -208,7 +216,7 @@ ___
 
 ▸ **privateToPublic**(`privateKey`: Buffer): *Buffer*
 
-*Defined in [account.ts:174](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L174)*
+*Defined in [account.ts:271](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L271)*
 
 Returns the ethereum public key of a given private key.
 
@@ -226,7 +234,7 @@ ___
 
 ▸ **pubToAddress**(`pubKey`: Buffer, `sanitize`: boolean): *Buffer*
 
-*Defined in [account.ts:151](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L151)*
+*Defined in [account.ts:248](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L248)*
 
 Returns the ethereum address of a given public key.
 Accepts "Ethereum public keys" and SEC1 encoded keys.
@@ -246,7 +254,7 @@ ___
 
 ▸ **toChecksumAddress**(`hexAddress`: string, `eip1191ChainId?`: undefined | number): *string*
 
-*Defined in [account.ts:45](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L45)*
+*Defined in [account.ts:142](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L142)*
 
 Returns a checksummed address.
 
@@ -272,7 +280,7 @@ ___
 
 ▸ **zeroAddress**(): *string*
 
-*Defined in [account.ts:12](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L12)*
+*Defined in [account.ts:291](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L291)*
 
 Returns a zero address.
 
diff --git a/docs/modules/_externals_.md b/docs/modules/_externals_.md
index 2d9a6773..6381f333 100644
--- a/docs/modules/_externals_.md
+++ b/docs/modules/_externals_.md
@@ -3,5 +3,4 @@
 # Module: "externals"
 
 Re-exports commonly used modules:
-* Adds [`ethjs-util`](https://github.com/ethjs/ethjs-util) methods.
 * Exports [`BN`](https://github.com/indutny/bn.js), [`rlp`](https://github.com/ethereumjs/rlp).
diff --git a/docs/modules/_hash_.md b/docs/modules/_hash_.md
index da56fa04..5f515614 100644
--- a/docs/modules/_hash_.md
+++ b/docs/modules/_hash_.md
@@ -44,7 +44,7 @@ ___
 
 ▸ **keccak256**(`a`: Buffer): *Buffer*
 
-*Defined in [hash.ts:24](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L24)*
+*Defined in [hash.ts:38](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L38)*
 
 Creates Keccak-256 hash of the input, alias for keccak(a, 256).
 
@@ -62,7 +62,7 @@ ___
 
 ▸ **keccakFromArray**(`a`: number[], `bits`: number): *Buffer‹›*
 
-*Defined in [hash.ts:54](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L54)*
+*Defined in [hash.ts:68](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L68)*
 
 Creates Keccak hash of a number array input
 
@@ -81,7 +81,7 @@ ___
 
 ▸ **keccakFromHexString**(`a`: string, `bits`: number): *Buffer‹›*
 
-*Defined in [hash.ts:44](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L44)*
+*Defined in [hash.ts:58](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L58)*
 
 Creates Keccak hash of an 0x-prefixed string input
 
@@ -100,7 +100,7 @@ ___
 
 ▸ **keccakFromString**(`a`: string, `bits`: number): *Buffer‹›*
 
-*Defined in [hash.ts:33](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L33)*
+*Defined in [hash.ts:47](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L47)*
 
 Creates Keccak hash of a utf-8 string input
 
@@ -119,7 +119,7 @@ ___
 
 ▸ **ripemd160**(`a`: Buffer, `padded`: boolean): *Buffer*
 
-*Defined in [hash.ts:102](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L102)*
+*Defined in [hash.ts:116](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L116)*
 
 Creates RIPEMD160 hash of a Buffer input.
 
@@ -138,7 +138,7 @@ ___
 
 ▸ **ripemd160FromArray**(`a`: number[], `padded`: boolean): *Buffer*
 
-*Defined in [hash.ts:122](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L122)*
+*Defined in [hash.ts:136](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L136)*
 
 Creates RIPEMD160 hash of a number[] input.
 
@@ -157,7 +157,7 @@ ___
 
 ▸ **ripemd160FromString**(`a`: string, `padded`: boolean): *Buffer*
 
-*Defined in [hash.ts:112](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L112)*
+*Defined in [hash.ts:126](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L126)*
 
 Creates RIPEMD160 hash of a string input.
 
@@ -176,7 +176,7 @@ ___
 
 ▸ **rlphash**(`a`: rlp.Input): *Buffer*
 
-*Defined in [hash.ts:148](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L148)*
+*Defined in [hash.ts:162](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L162)*
 
 Creates SHA-3 hash of the RLP encoded version of the input.
 
@@ -194,7 +194,7 @@ ___
 
 ▸ **sha256**(`a`: Buffer): *Buffer*
 
-*Defined in [hash.ts:63](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L63)*
+*Defined in [hash.ts:77](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L77)*
 
 Creates SHA256 hash of a Buffer input.
 
@@ -212,7 +212,7 @@ ___
 
 ▸ **sha256FromArray**(`a`: number[]): *Buffer*
 
-*Defined in [hash.ts:81](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L81)*
+*Defined in [hash.ts:95](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L95)*
 
 Creates SHA256 hash of a number[] input.
 
@@ -230,7 +230,7 @@ ___
 
 ▸ **sha256FromString**(`a`: string): *Buffer*
 
-*Defined in [hash.ts:72](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L72)*
+*Defined in [hash.ts:86](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/hash.ts#L86)*
 
 Creates SHA256 hash of a string input.
 
diff --git a/package.json b/package.json
index 2ee6ec6d..da275c6e 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
     "lint:fix": "ethereumjs-config-lint-fix",
     "test": "npm run lint && npm run test:node && npm run test:browser",
     "test:browser": "karma start karma.conf.js",
-    "test:node": "nyc --reporter=lcov mocha 'test/*.spec.ts' -- --require ts-node/register",
+    "test:node": "nyc --reporter=lcov mocha --require ts-node/register 'test/*.spec.ts'",
     "tsc": "ethereumjs-config-tsc",
     "tslint": "ethereumjs-config-tslint",
     "tslint:fix": "ethereumjs-config-tslint-fix"
diff --git a/src/account.ts b/src/account.ts
index 125ef2d9..ed2f0aed 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -1,23 +1,124 @@
-import * as ethjsUtil from 'ethjs-util'
+import * as assert from 'assert'
+import * as BN from 'bn.js'
+import * as rlp from 'rlp'
+import { stripHexPrefix } from 'ethjs-util'
+import { KECCAK256_RLP, KECCAK256_NULL } from './constants'
+import { zeros, bufferToHex, toBuffer, unpadBuffer } from './bytes'
+import { keccak, keccak256, keccakFromString, rlphash } from './hash'
+import { assertIsHexString, assertIsBuffer } from './helpers'
+
 const {
   privateKeyVerify,
   publicKeyCreate,
   publicKeyVerify,
   publicKeyConvert,
 } = require('ethereum-cryptography/secp256k1')
-import * as assert from 'assert'
-import * as BN from 'bn.js'
-import { zeros, bufferToHex } from './bytes'
-import { keccak, keccak256, keccakFromString, rlphash } from './hash'
-import { assertIsHexString, assertIsBuffer } from './helpers'
 
-/**
- * Returns a zero address.
- */
-export const zeroAddress = function(): string {
-  const addressLength = 20
-  const addr = zeros(addressLength)
-  return bufferToHex(addr)
+export interface AccountData {
+  nonce?: BNLike
+  balance?: BNLike
+  stateRoot?: BufferLike
+  codeHash?: BufferLike
+}
+
+type BNLike = BN | string | number
+
+type BufferLike = Buffer | TransformableToBuffer | PrefixedHexString | number
+
+type PrefixedHexString = string
+
+interface TransformableToBuffer {
+  toBuffer(): Buffer
+}
+
+/* Helper for Account.serialize() */
+function bnToRlp(value: BN): Buffer {
+  // using `bn.toArrayLike(Buffer)` instead of `bn.toBuffer()`
+  // for compatibility with browserify and similar tools
+  return unpadBuffer(value.toArrayLike(Buffer))
+}
+
+export class Account {
+  nonce: BN
+  balance: BN
+  stateRoot: Buffer
+  codeHash: Buffer
+
+  static fromAccountData(accountData: AccountData) {
+    const { nonce, balance, stateRoot, codeHash } = accountData
+
+    return new Account(
+      nonce ? new BN(toBuffer(nonce)) : undefined,
+      balance ? new BN(toBuffer(balance)) : undefined,
+      stateRoot ? toBuffer(stateRoot) : undefined,
+      codeHash ? toBuffer(codeHash) : undefined,
+    )
+  }
+
+  public static fromRlpSerializedAccount(serialized: Buffer) {
+    const values = rlp.decode(serialized)
+
+    if (!Array.isArray(values)) {
+      throw new Error('Invalid serialized account input. Must be array')
+    }
+
+    return this.fromValuesArray(values)
+  }
+
+  public static fromValuesArray(values: Buffer[]) {
+    const [nonce, balance, stateRoot, codeHash] = values
+
+    return new Account(
+      nonce ? new BN(nonce) : undefined,
+      balance ? new BN(balance) : undefined,
+      stateRoot,
+      codeHash,
+    )
+  }
+
+  /**
+   * This constructor takes the values, validates and assigns them.
+   * Use the static factory methods to assist in creating an Account from varying data types.
+   */
+  constructor(
+    nonce = new BN(0),
+    balance = new BN(0),
+    stateRoot = KECCAK256_RLP,
+    codeHash = KECCAK256_NULL,
+  ) {
+    if (stateRoot.length !== 32) {
+      throw new Error('stateRoot must have a length of 32')
+    }
+    if (codeHash.length !== 32) {
+      throw new Error('codeHash must have a length of 32')
+    }
+
+    this.nonce = nonce
+    this.balance = balance
+    this.stateRoot = stateRoot
+    this.codeHash = codeHash
+  }
+
+  /**
+   * Returns the RLP serialization of the account as a `Buffer`.
+   */
+  serialize(): Buffer {
+    return rlp.encode([bnToRlp(this.nonce), bnToRlp(this.balance), this.stateRoot, this.codeHash])
+  }
+
+  /**
+   * Returns a `Boolean` deteremining if the account is a contract.
+   */
+  isContract(): boolean {
+    return !this.codeHash.equals(KECCAK256_NULL)
+  }
+
+  /**
+   * Returns a `Boolean` determining if the account is empty.
+   */
+  isEmpty(): boolean {
+    return this.balance.isZero() && this.nonce.isZero() && this.codeHash.equals(KECCAK256_NULL)
+  }
 }
 
 /**
@@ -28,15 +129,6 @@ export const isValidAddress = function(hexAddress: string): boolean {
   return /^0x[0-9a-fA-F]{40}$/.test(hexAddress)
 }
 
-/**
- * Checks if a given address is a zero address.
- */
-export const isZeroAddress = function(hexAddress: string): boolean {
-  assertIsHexString(hexAddress)
-  const zeroAddr = zeroAddress()
-  return zeroAddr === hexAddress
-}
-
 /**
  * Returns a checksummed address.
  *
@@ -49,7 +141,7 @@ export const isZeroAddress = function(hexAddress: string): boolean {
  */
 export const toChecksumAddress = function(hexAddress: string, eip1191ChainId?: number): string {
   assertIsHexString(hexAddress)
-  const address = ethjsUtil.stripHexPrefix(hexAddress).toLowerCase()
+  const address = stripHexPrefix(hexAddress).toLowerCase()
 
   const prefix = eip1191ChainId !== undefined ? eip1191ChainId.toString() + '0x' : ''
 
@@ -192,3 +284,21 @@ export const importPublic = function(publicKey: Buffer): Buffer {
   }
   return publicKey
 }
+
+/**
+ * Returns a zero address.
+ */
+export const zeroAddress = function(): string {
+  const addressLength = 20
+  const addr = zeros(addressLength)
+  return bufferToHex(addr)
+}
+
+/**
+ * Checks if a given address is a zero address.
+ */
+export const isZeroAddress = function(hexAddress: string): boolean {
+  assertIsHexString(hexAddress)
+  const zeroAddr = zeroAddress()
+  return zeroAddr === hexAddress
+}
diff --git a/src/index.ts b/src/index.ts
index bf462b49..ff60d581 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -5,7 +5,7 @@
 export * from './constants'
 
 /**
- * Public-key cryptography (secp256k1) and addresses
+ * Account class and helper functions
  */
 export * from './account'
 
diff --git a/test/account.spec.ts b/test/account.spec.ts
index 44df2c17..241768ad 100644
--- a/test/account.spec.ts
+++ b/test/account.spec.ts
@@ -1,6 +1,8 @@
 import * as assert from 'assert'
 import * as BN from 'bn.js'
+import * as rlp from 'rlp'
 import {
+  Account,
   isValidPrivate,
   isValidPublic,
   importPublic,
@@ -16,6 +18,187 @@ import {
 } from '../src'
 const eip1014Testdata = require('./testdata/eip1014Examples.json')
 
+describe('Account', function() {
+  describe('empty constructor', function() {
+    const account = new Account()
+    it('should have zero nonce', function() {
+      assert.ok(account.nonce.isZero())
+    })
+    it('should have zero balance', function() {
+      assert.ok(account.balance.isZero())
+    })
+    it('should have stateRoot equal to KECCAK256_RLP', function() {
+      assert.ok(
+        account.stateRoot.toString('hex'),
+        '56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+      )
+    })
+    it('should have codeHash equal to KECCAK256_NULL', function() {
+      assert.equal(
+        account.codeHash.toString('hex'),
+        'c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+      )
+    })
+  })
+
+  describe('from Array data', function() {
+    const raw = [
+      '0x02', // nonce
+      '0x0384', // balance
+      '0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421', // stateRoot
+      '0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470', // codeHash
+    ]
+    const account = Account.fromValuesArray(raw.map(toBuffer))
+    it('should have correct nonce', function() {
+      assert.ok(account.nonce.eqn(2))
+    })
+    it('should have correct balance', function() {
+      assert.ok(account.balance.eqn(900))
+    })
+    it('should have correct stateRoot', function() {
+      assert.equal(
+        account.stateRoot.toString('hex'),
+        '56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+      )
+    })
+    it('should have correct codeHash', function() {
+      assert.equal(
+        account.codeHash.toString('hex'),
+        'c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+      )
+    })
+  })
+
+  describe('from Object data', function() {
+    const raw = {
+      nonce: '0x02',
+      balance: '0x0384',
+      stateRoot: '0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+      codeHash: '0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+    }
+    const account = Account.fromAccountData(raw)
+    it('should have correct nonce', function() {
+      assert.ok(account.nonce.eqn(2))
+    })
+    it('should have correct balance', function() {
+      assert.ok(account.balance.eqn(900))
+    })
+    it('should have correct stateRoot', function() {
+      assert.equal(
+        account.stateRoot.toString('hex'),
+        '56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+      )
+    })
+    it('should have correct codeHash', function() {
+      assert.equal(
+        account.codeHash.toString('hex'),
+        'c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+      )
+    })
+  })
+
+  describe('from RLP data', function() {
+    const accountRlp = Buffer.from(
+      'f84602820384a056e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421a0c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+      'hex',
+    )
+    const account = Account.fromRlpSerializedAccount(accountRlp)
+    it('should have correct nonce', function() {
+      assert.ok(account.nonce.eqn(2))
+    })
+    it('should have correct balance', function() {
+      assert.ok(account.balance.eqn(900))
+    })
+    it('should have correct stateRoot', function() {
+      assert.equal(
+        account.stateRoot.toString('hex'),
+        '56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+      )
+    })
+    it('should have correct codeHash', function() {
+      assert.equal(
+        account.codeHash.toString('hex'),
+        'c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+      )
+    })
+  })
+
+  describe('serialize', function() {
+    const raw = {
+      nonce: '0x01',
+      balance: '0x42',
+      stateRoot: '0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+      codeHash: '0xc5d2461236f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+    }
+    const account = Account.fromAccountData(raw)
+    const accountRlp = rlp.encode([raw.nonce, raw.balance, raw.stateRoot, raw.codeHash])
+    it('should serialize correctly', function() {
+      assert.ok(account.serialize().equals(accountRlp))
+    })
+  })
+
+  describe('isContract', function() {
+    it('should return false for a non-contract account', function() {
+      const accountRlp = Buffer.from(
+        'f84602820384a056e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421a0c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+        'hex',
+      )
+      const account = Account.fromRlpSerializedAccount(accountRlp)
+      assert.equal(account.isContract(), false)
+    })
+
+    it('should return true for a contract account', function() {
+      const raw = {
+        nonce: '0x01',
+        balance: '0x0042',
+        stateRoot: '0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+        codeHash: '0xc5d2461236f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+      }
+      const account = Account.fromAccountData(raw)
+      assert.ok(account.isContract())
+    })
+  })
+
+  describe('isEmpty', function() {
+    it('should return true for an empty account', function() {
+      const account = new Account()
+      assert.ok(account.isEmpty())
+    })
+
+    it('should return false for a non-empty account', function() {
+      const raw = {
+        nonce: '0x01',
+        balance: '0x0042',
+        stateRoot: '0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
+        codeHash: '0xc5d2461236f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+      }
+      const account = Account.fromAccountData(raw)
+      assert.equal(account.isEmpty(), false)
+    })
+  })
+
+  describe('validation', function() {
+    it('should only accept length 32 buffer for stateRoot', function() {
+      assert.throws(() => {
+        new Account(undefined, undefined, Buffer.from('hey'), undefined)
+      })
+    })
+
+    it('should only accept length 32 buffer for codeHash', function() {
+      assert.throws(() => {
+        new Account(undefined, undefined, undefined, Buffer.from('hey'))
+      })
+    })
+
+    it('should only accept an array in fromRlpSerializedAccount', function() {
+      const data = { balance: new BN(5) }
+      assert.throws(() => {
+        Account.fromRlpSerializedAccount(data as any)
+      })
+    })
+  })
+})
+
 describe('isValidPrivate', function() {
   const SECP256K1_N = new BN('fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141', 16)
   it('should fail on short input', function() {
@@ -196,112 +379,16 @@ describe('privateToPublic', function() {
   it('should produce a public key given a private key', function() {
     const pubKey =
       '3a443d8381a6798a70c6ff9304bdc8cb0163c23211d11628fae52ef9e0dca11a001cf066d56a8156fc201cd5df8a36ef694eecd258903fca7086c1fae7441e1d'
-    const privateKey = Buffer.from([
-      234,
-      84,
-      189,
-      197,
-      45,
-      22,
-      63,
-      136,
-      201,
-      58,
-      176,
-      97,
-      87,
-      130,
-      207,
-      113,
-      138,
-      46,
-      251,
-      158,
-      81,
-      167,
-      152,
-      154,
-      171,
-      27,
-      8,
-      6,
-      126,
-      156,
-      28,
-      95,
-    ])
+    // prettier-ignore
+    const privateKey = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28, 95,])
     const r: any = privateToPublic(privateKey).toString('hex')
     assert.equal(r.toString('hex'), pubKey)
   })
   it("shouldn't produce a public key given an invalid private key", function() {
-    const privateKey1 = Buffer.from([
-      234,
-      84,
-      189,
-      197,
-      45,
-      22,
-      63,
-      136,
-      201,
-      58,
-      176,
-      97,
-      87,
-      130,
-      207,
-      113,
-      138,
-      46,
-      251,
-      158,
-      81,
-      167,
-      152,
-      154,
-      171,
-      27,
-      8,
-      6,
-      126,
-      156,
-      28,
-      95,
-      42,
-    ])
-    const privateKey2 = Buffer.from([
-      234,
-      84,
-      189,
-      197,
-      45,
-      22,
-      63,
-      136,
-      201,
-      58,
-      176,
-      97,
-      87,
-      130,
-      207,
-      113,
-      138,
-      46,
-      251,
-      158,
-      81,
-      167,
-      152,
-      154,
-      171,
-      27,
-      8,
-      6,
-      126,
-      156,
-      28,
-    ])
+    // prettier-ignore
+    const privateKey1 = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28, 95, 42,])
+    // prettier-ignore
+    const privateKey2 = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28,])
     assert.throws(function() {
       privateToPublic(privateKey1)
     })
@@ -325,40 +412,8 @@ describe('privateToAddress', function() {
   it('should produce an address given a private key', function() {
     const address = '2f015c60e0be116b1f0cd534704db9c92118fb6a'
     // Our private key
-    const privateKey = Buffer.from([
-      234,
-      84,
-      189,
-      197,
-      45,
-      22,
-      63,
-      136,
-      201,
-      58,
-      176,
-      97,
-      87,
-      130,
-      207,
-      113,
-      138,
-      46,
-      251,
-      158,
-      81,
-      167,
-      152,
-      154,
-      171,
-      27,
-      8,
-      6,
-      126,
-      156,
-      28,
-      95,
-    ])
+    // prettier-ignore
+    const privateKey = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28, 95,])
     const r: any = privateToAddress(privateKey).toString('hex')
     assert.equal(r.toString('hex'), address)
   })
diff --git a/typedoc.js b/typedoc.js
index 3bf7fa03..c8e893a9 100644
--- a/typedoc.js
+++ b/typedoc.js
@@ -5,8 +5,8 @@ module.exports = {
   plugin: 'typedoc-plugin-markdown',
   readme: 'none',
   gitRevision: 'master',
-  exclude: '**/*+(index|.spec|.e2e).ts',
+  exclude: ['src/index.ts', 'test/*.ts'],
   excludeNotExported: true,
-  // excludePrivate: true,
-  // excludeProtected: true,
+  excludePrivate: true,
+  excludeProtected: true,
 }

From 3f858dbc5e58e7e86dbbe365b70b48244407b2d5 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Sun, 27 Sep 2020 20:06:32 -0700
Subject: [PATCH 02/11] export helpful types

---
 src/account.ts | 48 ++++++++++++++++--------------------------------
 src/helpers.ts | 24 ++++++++++++++++++------
 src/index.ts   |  7 ++++++-
 src/types.ts   | 11 +++++++++++
 4 files changed, 51 insertions(+), 39 deletions(-)
 create mode 100644 src/types.ts

diff --git a/src/account.ts b/src/account.ts
index ed2f0aed..cf5eca84 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -3,9 +3,10 @@ import * as BN from 'bn.js'
 import * as rlp from 'rlp'
 import { stripHexPrefix } from 'ethjs-util'
 import { KECCAK256_RLP, KECCAK256_NULL } from './constants'
-import { zeros, bufferToHex, toBuffer, unpadBuffer } from './bytes'
+import { zeros, bufferToHex, toBuffer } from './bytes'
 import { keccak, keccak256, keccakFromString, rlphash } from './hash'
-import { assertIsHexString, assertIsBuffer } from './helpers'
+import { assertIsHexString, assertIsBuffer, bnToRlp } from './helpers'
+import { BNLike, BufferLike } from './types'
 
 const {
   privateKeyVerify,
@@ -21,23 +22,6 @@ export interface AccountData {
   codeHash?: BufferLike
 }
 
-type BNLike = BN | string | number
-
-type BufferLike = Buffer | TransformableToBuffer | PrefixedHexString | number
-
-type PrefixedHexString = string
-
-interface TransformableToBuffer {
-  toBuffer(): Buffer
-}
-
-/* Helper for Account.serialize() */
-function bnToRlp(value: BN): Buffer {
-  // using `bn.toArrayLike(Buffer)` instead of `bn.toBuffer()`
-  // for compatibility with browserify and similar tools
-  return unpadBuffer(value.toArrayLike(Buffer))
-}
-
 export class Account {
   nonce: BN
   balance: BN
@@ -124,7 +108,7 @@ export class Account {
 /**
  * Checks if the address is a valid. Accepts checksummed addresses too.
  */
-export const isValidAddress = function(hexAddress: string): boolean {
+export const isValidAddress = function (hexAddress: string): boolean {
   assertIsHexString(hexAddress)
   return /^0x[0-9a-fA-F]{40}$/.test(hexAddress)
 }
@@ -139,7 +123,7 @@ export const isValidAddress = function(hexAddress: string): boolean {
  * WARNING: Checksums with and without the chainId will differ. As of 2019-06-26, the most commonly
  * used variation in Ethereum was without the chainId. This may change in the future.
  */
-export const toChecksumAddress = function(hexAddress: string, eip1191ChainId?: number): string {
+export const toChecksumAddress = function (hexAddress: string, eip1191ChainId?: number): string {
   assertIsHexString(hexAddress)
   const address = stripHexPrefix(hexAddress).toLowerCase()
 
@@ -164,7 +148,7 @@ export const toChecksumAddress = function(hexAddress: string, eip1191ChainId?: n
  *
  * See toChecksumAddress' documentation for details about the eip1191ChainId parameter.
  */
-export const isValidChecksumAddress = function(
+export const isValidChecksumAddress = function (
   hexAddress: string,
   eip1191ChainId?: number,
 ): boolean {
@@ -176,7 +160,7 @@ export const isValidChecksumAddress = function(
  * @param from The address which is creating this new address
  * @param nonce The nonce of the from account
  */
-export const generateAddress = function(from: Buffer, nonce: Buffer): Buffer {
+export const generateAddress = function (from: Buffer, nonce: Buffer): Buffer {
   assertIsBuffer(from)
   assertIsBuffer(nonce)
   const nonceBN = new BN(nonce)
@@ -197,7 +181,7 @@ export const generateAddress = function(from: Buffer, nonce: Buffer): Buffer {
  * @param salt A salt
  * @param initCode The init code of the contract being created
  */
-export const generateAddress2 = function(from: Buffer, salt: Buffer, initCode: Buffer): Buffer {
+export const generateAddress2 = function (from: Buffer, salt: Buffer, initCode: Buffer): Buffer {
   assertIsBuffer(from)
   assertIsBuffer(salt)
   assertIsBuffer(initCode)
@@ -215,7 +199,7 @@ export const generateAddress2 = function(from: Buffer, salt: Buffer, initCode: B
 /**
  * Checks if the private key satisfies the rules of the curve secp256k1.
  */
-export const isValidPrivate = function(privateKey: Buffer): boolean {
+export const isValidPrivate = function (privateKey: Buffer): boolean {
   return privateKeyVerify(privateKey)
 }
 
@@ -225,7 +209,7 @@ export const isValidPrivate = function(privateKey: Buffer): boolean {
  * @param publicKey The two points of an uncompressed key, unless sanitize is enabled
  * @param sanitize Accept public keys in other formats
  */
-export const isValidPublic = function(publicKey: Buffer, sanitize: boolean = false): boolean {
+export const isValidPublic = function (publicKey: Buffer, sanitize: boolean = false): boolean {
   assertIsBuffer(publicKey)
   if (publicKey.length === 64) {
     // Convert to SEC1 for secp256k1
@@ -245,7 +229,7 @@ export const isValidPublic = function(publicKey: Buffer, sanitize: boolean = fal
  * @param pubKey The two points of an uncompressed key, unless sanitize is enabled
  * @param sanitize Accept public keys in other formats
  */
-export const pubToAddress = function(pubKey: Buffer, sanitize: boolean = false): Buffer {
+export const pubToAddress = function (pubKey: Buffer, sanitize: boolean = false): Buffer {
   assertIsBuffer(pubKey)
   if (sanitize && pubKey.length !== 64) {
     pubKey = Buffer.from(publicKeyConvert(pubKey, false).slice(1))
@@ -260,7 +244,7 @@ export const publicToAddress = pubToAddress
  * Returns the ethereum address of a given private key.
  * @param privateKey A private key must be 256 bits wide
  */
-export const privateToAddress = function(privateKey: Buffer): Buffer {
+export const privateToAddress = function (privateKey: Buffer): Buffer {
   return publicToAddress(privateToPublic(privateKey))
 }
 
@@ -268,7 +252,7 @@ export const privateToAddress = function(privateKey: Buffer): Buffer {
  * Returns the ethereum public key of a given private key.
  * @param privateKey A private key must be 256 bits wide
  */
-export const privateToPublic = function(privateKey: Buffer): Buffer {
+export const privateToPublic = function (privateKey: Buffer): Buffer {
   assertIsBuffer(privateKey)
   // skip the type flag and use the X, Y points
   return Buffer.from(publicKeyCreate(privateKey, false)).slice(1)
@@ -277,7 +261,7 @@ export const privateToPublic = function(privateKey: Buffer): Buffer {
 /**
  * Converts a public key to the Ethereum format.
  */
-export const importPublic = function(publicKey: Buffer): Buffer {
+export const importPublic = function (publicKey: Buffer): Buffer {
   assertIsBuffer(publicKey)
   if (publicKey.length !== 64) {
     publicKey = Buffer.from(publicKeyConvert(publicKey, false).slice(1))
@@ -288,7 +272,7 @@ export const importPublic = function(publicKey: Buffer): Buffer {
 /**
  * Returns a zero address.
  */
-export const zeroAddress = function(): string {
+export const zeroAddress = function (): string {
   const addressLength = 20
   const addr = zeros(addressLength)
   return bufferToHex(addr)
@@ -297,7 +281,7 @@ export const zeroAddress = function(): string {
 /**
  * Checks if a given address is a zero address.
  */
-export const isZeroAddress = function(hexAddress: string): boolean {
+export const isZeroAddress = function (hexAddress: string): boolean {
   assertIsHexString(hexAddress)
   const zeroAddr = zeroAddress()
   return zeroAddr === hexAddress
diff --git a/src/helpers.ts b/src/helpers.ts
index 5f48ae39..2c027d75 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -1,11 +1,13 @@
-import * as ethjsUtil from 'ethjs-util'
+import * as BN from 'bn.js'
+import { isHexString } from 'ethjs-util'
+import { unpadBuffer } from './bytes'
 
 /**
  * Throws if a string is not hex prefixed
  * @param {string} input string to check hex prefix of
  */
-export const assertIsHexString = function(input: string): void {
-  if (!ethjsUtil.isHexString(input)) {
+export const assertIsHexString = function (input: string): void {
+  if (!isHexString(input)) {
     const msg = `This method only supports 0x-prefixed hex strings but input was: ${input}`
     throw new Error(msg)
   }
@@ -15,7 +17,7 @@ export const assertIsHexString = function(input: string): void {
  * Throws if input is not a buffer
  * @param {Buffer} input value to check
  */
-export const assertIsBuffer = function(input: Buffer): void {
+export const assertIsBuffer = function (input: Buffer): void {
   if (!Buffer.isBuffer(input)) {
     const msg = `This method only supports Buffer but input was: ${input}`
     throw new Error(msg)
@@ -26,7 +28,7 @@ export const assertIsBuffer = function(input: Buffer): void {
  * Throws if input is not an array
  * @param {number[]} input value to check
  */
-export const assertIsArray = function(input: number[]): void {
+export const assertIsArray = function (input: number[]): void {
   if (!Array.isArray(input)) {
     const msg = `This method only supports number arrays but input was: ${input}`
     throw new Error(msg)
@@ -37,9 +39,19 @@ export const assertIsArray = function(input: number[]): void {
  * Throws if input is not a string
  * @param {string} input value to check
  */
-export const assertIsString = function(input: string): void {
+export const assertIsString = function (input: string): void {
   if (typeof input !== 'string') {
     const msg = `This method only supports strings but input was: ${input}`
     throw new Error(msg)
   }
 }
+
+/**
+ * Convert value from BN to RLP (unpadded buffer)
+ * @param value value to convert
+ */
+export function bnToRlp(value: BN): Buffer {
+  // Using `bn.toArrayLike(Buffer)` instead of `bn.toBuffer()`
+  // for compatibility with browserify and similar tools
+  return unpadBuffer(value.toArrayLike(Buffer))
+}
\ No newline at end of file
diff --git a/src/index.ts b/src/index.ts
index ff60d581..971a2876 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -39,7 +39,12 @@ export * from './object'
  */
 export * from './externals'
 
+/**
+ * Helpful TypeScript types
+ */
+export * from './types'
+
 /**
  * Export ethjs-util methods
  */
-export * from 'ethjs-util'
+export * from 'ethjs-util'
\ No newline at end of file
diff --git a/src/types.ts b/src/types.ts
new file mode 100644
index 00000000..02618431
--- /dev/null
+++ b/src/types.ts
@@ -0,0 +1,11 @@
+import * as BN from 'bn.js'
+
+export type BNLike = BN | string | number
+
+export type BufferLike = Buffer | TransformableToBuffer | PrefixedHexString | number
+
+export type PrefixedHexString = string
+
+export interface TransformableToBuffer {
+    toBuffer(): Buffer
+}
\ No newline at end of file

From cfe8a9a13d94a4d2c9ac05d2e590261f7b9a3f5b Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Sun, 27 Sep 2020 20:14:55 -0700
Subject: [PATCH 03/11] check stateRoot in isEmpty

---
 src/account.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/account.ts b/src/account.ts
index cf5eca84..af9dc324 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -101,7 +101,7 @@ export class Account {
    * Returns a `Boolean` determining if the account is empty.
    */
   isEmpty(): boolean {
-    return this.balance.isZero() && this.nonce.isZero() && this.codeHash.equals(KECCAK256_NULL)
+    return this.balance.isZero() && this.nonce.isZero() && this.stateRoot.equals(KECCAK256_RLP) && this.codeHash.equals(KECCAK256_NULL)
   }
 }
 

From 6c89111e4b60b4fd3a1d98205199d6d274b61959 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Sun, 27 Sep 2020 20:15:42 -0700
Subject: [PATCH 04/11] use hex strings for private keys

---
 test/account.spec.ts | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/test/account.spec.ts b/test/account.spec.ts
index 241768ad..2548fbfa 100644
--- a/test/account.spec.ts
+++ b/test/account.spec.ts
@@ -379,16 +379,22 @@ describe('privateToPublic', function() {
   it('should produce a public key given a private key', function() {
     const pubKey =
       '3a443d8381a6798a70c6ff9304bdc8cb0163c23211d11628fae52ef9e0dca11a001cf066d56a8156fc201cd5df8a36ef694eecd258903fca7086c1fae7441e1d'
-    // prettier-ignore
-    const privateKey = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28, 95,])
+    const privateKey = Buffer.from(
+      'ea54bdc52d163f88c93ab0615782cf718a2efb9e51a7989aab1b08067e9c1c5f',
+      'hex',
+    )
     const r: any = privateToPublic(privateKey).toString('hex')
     assert.equal(r.toString('hex'), pubKey)
   })
   it("shouldn't produce a public key given an invalid private key", function() {
-    // prettier-ignore
-    const privateKey1 = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28, 95, 42,])
-    // prettier-ignore
-    const privateKey2 = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28,])
+    const privateKey1 = Buffer.from(
+      'ea54bdc52d163f88c93ab0615782cf718a2efb9e51a7989aab1b08067e9c1c5f2a',
+      'hex',
+    )
+    const privateKey2 = Buffer.from(
+      'ea54bdc52d163f88c93ab0615782cf718a2efb9e51a7989aab1b08067e9c1c',
+      'hex',
+    )
     assert.throws(function() {
       privateToPublic(privateKey1)
     })
@@ -412,8 +418,10 @@ describe('privateToAddress', function() {
   it('should produce an address given a private key', function() {
     const address = '2f015c60e0be116b1f0cd534704db9c92118fb6a'
     // Our private key
-    // prettier-ignore
-    const privateKey = Buffer.from([234, 84, 189, 197, 45, 22, 63, 136, 201, 58, 176, 97, 87, 130, 207, 113, 138, 46, 251, 158, 81, 167, 152, 154, 171, 27, 8, 6, 126, 156, 28, 95,])
+    const privateKey = Buffer.from(
+      'ea54bdc52d163f88c93ab0615782cf718a2efb9e51a7989aab1b08067e9c1c5f',
+      'hex',
+    )
     const r: any = privateToAddress(privateKey).toString('hex')
     assert.equal(r.toString('hex'), address)
   })

From 18e90bff7b301e030567a311a2796610d7b5d327 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Sun, 27 Sep 2020 20:15:47 -0700
Subject: [PATCH 05/11] lint

---
 src/account.ts | 33 +++++++++++++++++++--------------
 src/helpers.ts | 10 +++++-----
 src/index.ts   |  2 +-
 src/types.ts   |  4 ++--
 4 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/src/account.ts b/src/account.ts
index af9dc324..77fae23f 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -101,14 +101,19 @@ export class Account {
    * Returns a `Boolean` determining if the account is empty.
    */
   isEmpty(): boolean {
-    return this.balance.isZero() && this.nonce.isZero() && this.stateRoot.equals(KECCAK256_RLP) && this.codeHash.equals(KECCAK256_NULL)
+    return (
+      this.balance.isZero() &&
+      this.nonce.isZero() &&
+      this.stateRoot.equals(KECCAK256_RLP) &&
+      this.codeHash.equals(KECCAK256_NULL)
+    )
   }
 }
 
 /**
  * Checks if the address is a valid. Accepts checksummed addresses too.
  */
-export const isValidAddress = function (hexAddress: string): boolean {
+export const isValidAddress = function(hexAddress: string): boolean {
   assertIsHexString(hexAddress)
   return /^0x[0-9a-fA-F]{40}$/.test(hexAddress)
 }
@@ -123,7 +128,7 @@ export const isValidAddress = function (hexAddress: string): boolean {
  * WARNING: Checksums with and without the chainId will differ. As of 2019-06-26, the most commonly
  * used variation in Ethereum was without the chainId. This may change in the future.
  */
-export const toChecksumAddress = function (hexAddress: string, eip1191ChainId?: number): string {
+export const toChecksumAddress = function(hexAddress: string, eip1191ChainId?: number): string {
   assertIsHexString(hexAddress)
   const address = stripHexPrefix(hexAddress).toLowerCase()
 
@@ -148,7 +153,7 @@ export const toChecksumAddress = function (hexAddress: string, eip1191ChainId?:
  *
  * See toChecksumAddress' documentation for details about the eip1191ChainId parameter.
  */
-export const isValidChecksumAddress = function (
+export const isValidChecksumAddress = function(
   hexAddress: string,
   eip1191ChainId?: number,
 ): boolean {
@@ -160,7 +165,7 @@ export const isValidChecksumAddress = function (
  * @param from The address which is creating this new address
  * @param nonce The nonce of the from account
  */
-export const generateAddress = function (from: Buffer, nonce: Buffer): Buffer {
+export const generateAddress = function(from: Buffer, nonce: Buffer): Buffer {
   assertIsBuffer(from)
   assertIsBuffer(nonce)
   const nonceBN = new BN(nonce)
@@ -181,7 +186,7 @@ export const generateAddress = function (from: Buffer, nonce: Buffer): Buffer {
  * @param salt A salt
  * @param initCode The init code of the contract being created
  */
-export const generateAddress2 = function (from: Buffer, salt: Buffer, initCode: Buffer): Buffer {
+export const generateAddress2 = function(from: Buffer, salt: Buffer, initCode: Buffer): Buffer {
   assertIsBuffer(from)
   assertIsBuffer(salt)
   assertIsBuffer(initCode)
@@ -199,7 +204,7 @@ export const generateAddress2 = function (from: Buffer, salt: Buffer, initCode:
 /**
  * Checks if the private key satisfies the rules of the curve secp256k1.
  */
-export const isValidPrivate = function (privateKey: Buffer): boolean {
+export const isValidPrivate = function(privateKey: Buffer): boolean {
   return privateKeyVerify(privateKey)
 }
 
@@ -209,7 +214,7 @@ export const isValidPrivate = function (privateKey: Buffer): boolean {
  * @param publicKey The two points of an uncompressed key, unless sanitize is enabled
  * @param sanitize Accept public keys in other formats
  */
-export const isValidPublic = function (publicKey: Buffer, sanitize: boolean = false): boolean {
+export const isValidPublic = function(publicKey: Buffer, sanitize: boolean = false): boolean {
   assertIsBuffer(publicKey)
   if (publicKey.length === 64) {
     // Convert to SEC1 for secp256k1
@@ -229,7 +234,7 @@ export const isValidPublic = function (publicKey: Buffer, sanitize: boolean = fa
  * @param pubKey The two points of an uncompressed key, unless sanitize is enabled
  * @param sanitize Accept public keys in other formats
  */
-export const pubToAddress = function (pubKey: Buffer, sanitize: boolean = false): Buffer {
+export const pubToAddress = function(pubKey: Buffer, sanitize: boolean = false): Buffer {
   assertIsBuffer(pubKey)
   if (sanitize && pubKey.length !== 64) {
     pubKey = Buffer.from(publicKeyConvert(pubKey, false).slice(1))
@@ -244,7 +249,7 @@ export const publicToAddress = pubToAddress
  * Returns the ethereum address of a given private key.
  * @param privateKey A private key must be 256 bits wide
  */
-export const privateToAddress = function (privateKey: Buffer): Buffer {
+export const privateToAddress = function(privateKey: Buffer): Buffer {
   return publicToAddress(privateToPublic(privateKey))
 }
 
@@ -252,7 +257,7 @@ export const privateToAddress = function (privateKey: Buffer): Buffer {
  * Returns the ethereum public key of a given private key.
  * @param privateKey A private key must be 256 bits wide
  */
-export const privateToPublic = function (privateKey: Buffer): Buffer {
+export const privateToPublic = function(privateKey: Buffer): Buffer {
   assertIsBuffer(privateKey)
   // skip the type flag and use the X, Y points
   return Buffer.from(publicKeyCreate(privateKey, false)).slice(1)
@@ -261,7 +266,7 @@ export const privateToPublic = function (privateKey: Buffer): Buffer {
 /**
  * Converts a public key to the Ethereum format.
  */
-export const importPublic = function (publicKey: Buffer): Buffer {
+export const importPublic = function(publicKey: Buffer): Buffer {
   assertIsBuffer(publicKey)
   if (publicKey.length !== 64) {
     publicKey = Buffer.from(publicKeyConvert(publicKey, false).slice(1))
@@ -272,7 +277,7 @@ export const importPublic = function (publicKey: Buffer): Buffer {
 /**
  * Returns a zero address.
  */
-export const zeroAddress = function (): string {
+export const zeroAddress = function(): string {
   const addressLength = 20
   const addr = zeros(addressLength)
   return bufferToHex(addr)
@@ -281,7 +286,7 @@ export const zeroAddress = function (): string {
 /**
  * Checks if a given address is a zero address.
  */
-export const isZeroAddress = function (hexAddress: string): boolean {
+export const isZeroAddress = function(hexAddress: string): boolean {
   assertIsHexString(hexAddress)
   const zeroAddr = zeroAddress()
   return zeroAddr === hexAddress
diff --git a/src/helpers.ts b/src/helpers.ts
index 2c027d75..bcceaa22 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -6,7 +6,7 @@ import { unpadBuffer } from './bytes'
  * Throws if a string is not hex prefixed
  * @param {string} input string to check hex prefix of
  */
-export const assertIsHexString = function (input: string): void {
+export const assertIsHexString = function(input: string): void {
   if (!isHexString(input)) {
     const msg = `This method only supports 0x-prefixed hex strings but input was: ${input}`
     throw new Error(msg)
@@ -17,7 +17,7 @@ export const assertIsHexString = function (input: string): void {
  * Throws if input is not a buffer
  * @param {Buffer} input value to check
  */
-export const assertIsBuffer = function (input: Buffer): void {
+export const assertIsBuffer = function(input: Buffer): void {
   if (!Buffer.isBuffer(input)) {
     const msg = `This method only supports Buffer but input was: ${input}`
     throw new Error(msg)
@@ -28,7 +28,7 @@ export const assertIsBuffer = function (input: Buffer): void {
  * Throws if input is not an array
  * @param {number[]} input value to check
  */
-export const assertIsArray = function (input: number[]): void {
+export const assertIsArray = function(input: number[]): void {
   if (!Array.isArray(input)) {
     const msg = `This method only supports number arrays but input was: ${input}`
     throw new Error(msg)
@@ -39,7 +39,7 @@ export const assertIsArray = function (input: number[]): void {
  * Throws if input is not a string
  * @param {string} input value to check
  */
-export const assertIsString = function (input: string): void {
+export const assertIsString = function(input: string): void {
   if (typeof input !== 'string') {
     const msg = `This method only supports strings but input was: ${input}`
     throw new Error(msg)
@@ -54,4 +54,4 @@ export function bnToRlp(value: BN): Buffer {
   // Using `bn.toArrayLike(Buffer)` instead of `bn.toBuffer()`
   // for compatibility with browserify and similar tools
   return unpadBuffer(value.toArrayLike(Buffer))
-}
\ No newline at end of file
+}
diff --git a/src/index.ts b/src/index.ts
index 971a2876..848d0c77 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -47,4 +47,4 @@ export * from './types'
 /**
  * Export ethjs-util methods
  */
-export * from 'ethjs-util'
\ No newline at end of file
+export * from 'ethjs-util'
diff --git a/src/types.ts b/src/types.ts
index 02618431..894c9133 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -7,5 +7,5 @@ export type BufferLike = Buffer | TransformableToBuffer | PrefixedHexString | nu
 export type PrefixedHexString = string
 
 export interface TransformableToBuffer {
-    toBuffer(): Buffer
-}
\ No newline at end of file
+  toBuffer(): Buffer
+}

From 0f5418ef1d86d0d3c54cfcb01df76352205b2888 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Sun, 27 Sep 2020 20:26:06 -0700
Subject: [PATCH 06/11] rebuild docs, add types docs

---
 CHANGELOG.md                                  |  8 ++++
 README.md                                     |  2 +
 docs/README.md                                |  1 +
 docs/classes/_account_.account.md             | 22 +++++------
 docs/interfaces/_account_.accountdata.md      | 16 ++++----
 .../_types_.transformabletobuffer.md          | 23 +++++++++++
 docs/modules/_account_.md                     | 28 ++++++-------
 docs/modules/_helpers_.md                     | 27 +++++++++++--
 docs/modules/_types_.md                       | 39 +++++++++++++++++++
 9 files changed, 129 insertions(+), 37 deletions(-)
 create mode 100644 docs/interfaces/_types_.transformabletobuffer.md
 create mode 100644 docs/modules/_types_.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d4474e09..14a8b6f0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 
 ## [7.0.6] - [UNRELEASED]
 
+### New `Account` class
+
 This release adds a new `Account` class intended as a modern replacement for `ethereumjs-account`. It has a shape of `Account(nonce?: BN, balance?: BN, stateRoot?: Buffer, codeHash?: Buffer)`.
 
 **Instantiation**
@@ -31,6 +33,12 @@ const account = new Account(
 
 For more info see the documentation or examples of usage in `test/account.spec.ts`.
 
+### New export: TypeScript types
+
+A new file with helpful TypeScript types has been added to the exports of this project.
+
+In this release it contains `BNLike`, `BufferLike`, and `TransformableToBuffer`.
+
 ## [7.0.5] - 2020-09-09
 
 This release adds a new module `address` - see [README](https://github.com/ethereumjs/ethereumjs-util#modules) -
diff --git a/README.md b/README.md
index 654c9561..1d22e35c 100644
--- a/README.md
+++ b/README.md
@@ -47,6 +47,8 @@ assert.equal(new BN('dead', 16).add(new BN('101010', 2)), 57047)
   - Helper function for creating a binary object (`DEPRECATED`)
 - [signature](docs/modules/_signature_.md)
   - Signing, signature validation, conversion, recovery
+- [types](docs/modules/_types_.md)
+  - Helpful TypeScript types
 - [externals](docs/modules/_externals_.md)
   - Helper methods from `ethjs-util`
   - Re-exports of `BN`, `rlp`
diff --git a/docs/README.md b/docs/README.md
index 7dff9c06..bdfde4cb 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -16,3 +16,4 @@
 * ["helpers"](modules/_helpers_.md)
 * ["object"](modules/_object_.md)
 * ["signature"](modules/_signature_.md)
+* ["types"](modules/_types_.md)
diff --git a/docs/classes/_account_.account.md b/docs/classes/_account_.account.md
index 4f3d33d8..42391678 100644
--- a/docs/classes/_account_.account.md
+++ b/docs/classes/_account_.account.md
@@ -34,7 +34,7 @@
 
 \+ **new Account**(`nonce`: BN‹›, `balance`: BN‹›, `stateRoot`: Buffer‹›, `codeHash`: Buffer‹›): *[Account](_account_.account.md)*
 
-*Defined in [account.ts:77](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L77)*
+*Defined in [account.ts:61](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L61)*
 
 This constructor takes the values, validates and assigns them.
 Use the static factory methods to assist in creating an Account from varying data types.
@@ -56,7 +56,7 @@ Name | Type | Default |
 
 • **balance**: *BN*
 
-*Defined in [account.ts:43](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L43)*
+*Defined in [account.ts:27](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L27)*
 
 ___
 
@@ -64,7 +64,7 @@ ___
 
 • **codeHash**: *Buffer*
 
-*Defined in [account.ts:45](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L45)*
+*Defined in [account.ts:29](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L29)*
 
 ___
 
@@ -72,7 +72,7 @@ ___
 
 • **nonce**: *BN*
 
-*Defined in [account.ts:42](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L42)*
+*Defined in [account.ts:26](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L26)*
 
 ___
 
@@ -80,7 +80,7 @@ ___
 
 • **stateRoot**: *Buffer*
 
-*Defined in [account.ts:44](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L44)*
+*Defined in [account.ts:28](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L28)*
 
 ## Methods
 
@@ -88,7 +88,7 @@ ___
 
 ▸ **isContract**(): *boolean*
 
-*Defined in [account.ts:112](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L112)*
+*Defined in [account.ts:96](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L96)*
 
 Returns a `Boolean` deteremining if the account is a contract.
 
@@ -100,7 +100,7 @@ ___
 
 ▸ **isEmpty**(): *boolean*
 
-*Defined in [account.ts:119](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L119)*
+*Defined in [account.ts:103](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L103)*
 
 Returns a `Boolean` determining if the account is empty.
 
@@ -112,7 +112,7 @@ ___
 
 ▸ **serialize**(): *Buffer*
 
-*Defined in [account.ts:105](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L105)*
+*Defined in [account.ts:89](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L89)*
 
 Returns the RLP serialization of the account as a `Buffer`.
 
@@ -124,7 +124,7 @@ ___
 
 ▸ **fromAccountData**(`accountData`: [AccountData](../interfaces/_account_.accountdata.md)): *[Account](_account_.account.md)‹›*
 
-*Defined in [account.ts:47](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L47)*
+*Defined in [account.ts:31](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L31)*
 
 **Parameters:**
 
@@ -140,7 +140,7 @@ ___
 
 ▸ **fromRlpSerializedAccount**(`serialized`: Buffer): *[Account](_account_.account.md)‹›*
 
-*Defined in [account.ts:58](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L58)*
+*Defined in [account.ts:42](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L42)*
 
 **Parameters:**
 
@@ -156,7 +156,7 @@ ___
 
 ▸ **fromValuesArray**(`values`: Buffer[]): *[Account](_account_.account.md)‹›*
 
-*Defined in [account.ts:68](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L68)*
+*Defined in [account.ts:52](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L52)*
 
 **Parameters:**
 
diff --git a/docs/interfaces/_account_.accountdata.md b/docs/interfaces/_account_.accountdata.md
index 698b49df..126266a0 100644
--- a/docs/interfaces/_account_.accountdata.md
+++ b/docs/interfaces/_account_.accountdata.md
@@ -19,30 +19,30 @@
 
 ### `Optional` balance
 
-• **balance**? : *BNLike*
+• **balance**? : *[BNLike](../modules/_types_.md#bnlike)*
 
-*Defined in [account.ts:19](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L19)*
+*Defined in [account.ts:20](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L20)*
 
 ___
 
 ### `Optional` codeHash
 
-• **codeHash**? : *BufferLike*
+• **codeHash**? : *[BufferLike](../modules/_types_.md#bufferlike)*
 
-*Defined in [account.ts:21](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L21)*
+*Defined in [account.ts:22](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L22)*
 
 ___
 
 ### `Optional` nonce
 
-• **nonce**? : *BNLike*
+• **nonce**? : *[BNLike](../modules/_types_.md#bnlike)*
 
-*Defined in [account.ts:18](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L18)*
+*Defined in [account.ts:19](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L19)*
 
 ___
 
 ### `Optional` stateRoot
 
-• **stateRoot**? : *BufferLike*
+• **stateRoot**? : *[BufferLike](../modules/_types_.md#bufferlike)*
 
-*Defined in [account.ts:20](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L20)*
+*Defined in [account.ts:21](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L21)*
diff --git a/docs/interfaces/_types_.transformabletobuffer.md b/docs/interfaces/_types_.transformabletobuffer.md
new file mode 100644
index 00000000..7ab3daaf
--- /dev/null
+++ b/docs/interfaces/_types_.transformabletobuffer.md
@@ -0,0 +1,23 @@
+[ethereumjs-util](../README.md) › ["types"](../modules/_types_.md) › [TransformableToBuffer](_types_.transformabletobuffer.md)
+
+# Interface: TransformableToBuffer
+
+## Hierarchy
+
+* **TransformableToBuffer**
+
+## Index
+
+### Methods
+
+* [toBuffer](_types_.transformabletobuffer.md#tobuffer)
+
+## Methods
+
+###  toBuffer
+
+▸ **toBuffer**(): *Buffer*
+
+*Defined in [types.ts:10](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/types.ts#L10)*
+
+**Returns:** *Buffer*
diff --git a/docs/modules/_account_.md b/docs/modules/_account_.md
index 08125b1d..0abc65de 100644
--- a/docs/modules/_account_.md
+++ b/docs/modules/_account_.md
@@ -38,7 +38,7 @@
 
 • **publicToAddress**: *pubToAddress* = pubToAddress
 
-*Defined in [account.ts:257](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L257)*
+*Defined in [account.ts:246](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L246)*
 
 ## Functions
 
@@ -46,7 +46,7 @@
 
 ▸ **generateAddress**(`from`: Buffer, `nonce`: Buffer): *Buffer*
 
-*Defined in [account.ts:179](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L179)*
+*Defined in [account.ts:168](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L168)*
 
 Generates an address of a newly created contract.
 
@@ -65,7 +65,7 @@ ___
 
 ▸ **generateAddress2**(`from`: Buffer, `salt`: Buffer, `initCode`: Buffer): *Buffer*
 
-*Defined in [account.ts:200](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L200)*
+*Defined in [account.ts:189](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L189)*
 
 Generates an address for a contract created using CREATE2.
 
@@ -85,7 +85,7 @@ ___
 
 ▸ **importPublic**(`publicKey`: Buffer): *Buffer*
 
-*Defined in [account.ts:280](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L280)*
+*Defined in [account.ts:269](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L269)*
 
 Converts a public key to the Ethereum format.
 
@@ -103,7 +103,7 @@ ___
 
 ▸ **isValidAddress**(`hexAddress`: string): *boolean*
 
-*Defined in [account.ts:127](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L127)*
+*Defined in [account.ts:116](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L116)*
 
 Checks if the address is a valid. Accepts checksummed addresses too.
 
@@ -121,7 +121,7 @@ ___
 
 ▸ **isValidChecksumAddress**(`hexAddress`: string, `eip1191ChainId?`: undefined | number): *boolean*
 
-*Defined in [account.ts:167](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L167)*
+*Defined in [account.ts:156](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L156)*
 
 Checks if the address is a valid checksummed address.
 
@@ -142,7 +142,7 @@ ___
 
 ▸ **isValidPrivate**(`privateKey`: Buffer): *boolean*
 
-*Defined in [account.ts:218](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L218)*
+*Defined in [account.ts:207](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L207)*
 
 Checks if the private key satisfies the rules of the curve secp256k1.
 
@@ -160,7 +160,7 @@ ___
 
 ▸ **isValidPublic**(`publicKey`: Buffer, `sanitize`: boolean): *boolean*
 
-*Defined in [account.ts:228](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L228)*
+*Defined in [account.ts:217](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L217)*
 
 Checks if the public key satisfies the rules of the curve secp256k1
 and the requirements of Ethereum.
@@ -180,7 +180,7 @@ ___
 
 ▸ **isZeroAddress**(`hexAddress`: string): *boolean*
 
-*Defined in [account.ts:300](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L300)*
+*Defined in [account.ts:289](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L289)*
 
 Checks if a given address is a zero address.
 
@@ -198,7 +198,7 @@ ___
 
 ▸ **privateToAddress**(`privateKey`: Buffer): *Buffer*
 
-*Defined in [account.ts:263](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L263)*
+*Defined in [account.ts:252](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L252)*
 
 Returns the ethereum address of a given private key.
 
@@ -216,7 +216,7 @@ ___
 
 ▸ **privateToPublic**(`privateKey`: Buffer): *Buffer*
 
-*Defined in [account.ts:271](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L271)*
+*Defined in [account.ts:260](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L260)*
 
 Returns the ethereum public key of a given private key.
 
@@ -234,7 +234,7 @@ ___
 
 ▸ **pubToAddress**(`pubKey`: Buffer, `sanitize`: boolean): *Buffer*
 
-*Defined in [account.ts:248](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L248)*
+*Defined in [account.ts:237](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L237)*
 
 Returns the ethereum address of a given public key.
 Accepts "Ethereum public keys" and SEC1 encoded keys.
@@ -254,7 +254,7 @@ ___
 
 ▸ **toChecksumAddress**(`hexAddress`: string, `eip1191ChainId?`: undefined | number): *string*
 
-*Defined in [account.ts:142](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L142)*
+*Defined in [account.ts:131](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L131)*
 
 Returns a checksummed address.
 
@@ -280,7 +280,7 @@ ___
 
 ▸ **zeroAddress**(): *string*
 
-*Defined in [account.ts:291](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L291)*
+*Defined in [account.ts:280](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/account.ts#L280)*
 
 Returns a zero address.
 
diff --git a/docs/modules/_helpers_.md b/docs/modules/_helpers_.md
index 70afc005..5f6b892b 100644
--- a/docs/modules/_helpers_.md
+++ b/docs/modules/_helpers_.md
@@ -10,6 +10,7 @@
 * [assertIsBuffer](_helpers_.md#const-assertisbuffer)
 * [assertIsHexString](_helpers_.md#const-assertishexstring)
 * [assertIsString](_helpers_.md#const-assertisstring)
+* [bnToRlp](_helpers_.md#bntorlp)
 
 ## Functions
 
@@ -17,7 +18,7 @@
 
 ▸ **assertIsArray**(`input`: number[]): *void*
 
-*Defined in [helpers.ts:29](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L29)*
+*Defined in [helpers.ts:31](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L31)*
 
 Throws if input is not an array
 
@@ -35,7 +36,7 @@ ___
 
 ▸ **assertIsBuffer**(`input`: Buffer): *void*
 
-*Defined in [helpers.ts:18](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L18)*
+*Defined in [helpers.ts:20](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L20)*
 
 Throws if input is not a buffer
 
@@ -53,7 +54,7 @@ ___
 
 ▸ **assertIsHexString**(`input`: string): *void*
 
-*Defined in [helpers.ts:7](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L7)*
+*Defined in [helpers.ts:9](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L9)*
 
 Throws if a string is not hex prefixed
 
@@ -71,7 +72,7 @@ ___
 
 ▸ **assertIsString**(`input`: string): *void*
 
-*Defined in [helpers.ts:40](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L40)*
+*Defined in [helpers.ts:42](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L42)*
 
 Throws if input is not a string
 
@@ -82,3 +83,21 @@ Name | Type | Description |
 `input` | string | value to check  |
 
 **Returns:** *void*
+
+___
+
+###  bnToRlp
+
+▸ **bnToRlp**(`value`: BN): *Buffer*
+
+*Defined in [helpers.ts:53](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/helpers.ts#L53)*
+
+Convert value from BN to RLP (unpadded buffer)
+
+**Parameters:**
+
+Name | Type | Description |
+------ | ------ | ------ |
+`value` | BN | value to convert  |
+
+**Returns:** *Buffer*
diff --git a/docs/modules/_types_.md b/docs/modules/_types_.md
new file mode 100644
index 00000000..bf0509b6
--- /dev/null
+++ b/docs/modules/_types_.md
@@ -0,0 +1,39 @@
+[ethereumjs-util](../README.md) › ["types"](_types_.md)
+
+# Module: "types"
+
+## Index
+
+### Interfaces
+
+* [TransformableToBuffer](../interfaces/_types_.transformabletobuffer.md)
+
+### Type aliases
+
+* [BNLike](_types_.md#bnlike)
+* [BufferLike](_types_.md#bufferlike)
+* [PrefixedHexString](_types_.md#prefixedhexstring)
+
+## Type aliases
+
+###  BNLike
+
+Ƭ **BNLike**: *BN | string | number*
+
+*Defined in [types.ts:3](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/types.ts#L3)*
+
+___
+
+###  BufferLike
+
+Ƭ **BufferLike**: *Buffer | [TransformableToBuffer](../interfaces/_types_.transformabletobuffer.md) | [PrefixedHexString](_types_.md#prefixedhexstring) | number*
+
+*Defined in [types.ts:5](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/types.ts#L5)*
+
+___
+
+###  PrefixedHexString
+
+Ƭ **PrefixedHexString**: *string*
+
+*Defined in [types.ts:7](https://github.com/ethereumjs/ethereumjs-util/blob/master/src/types.ts#L7)*

From b2fce00e9b330417a3719f7a26329acede43746f Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Mon, 28 Sep 2020 12:46:29 -0700
Subject: [PATCH 07/11] fix typo

---
 src/account.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/account.ts b/src/account.ts
index 77fae23f..b057b93a 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -91,7 +91,7 @@ export class Account {
   }
 
   /**
-   * Returns a `Boolean` deteremining if the account is a contract.
+   * Returns a `Boolean` determining if the account is a contract.
    */
   isContract(): boolean {
     return !this.codeHash.equals(KECCAK256_NULL)

From 36a070008a4048461d315db487cfbe9f83e16b24 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Mon, 28 Sep 2020 12:47:22 -0700
Subject: [PATCH 08/11] make codeHash more different-looking than
 KECCAK256_NULL

---
 test/account.spec.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/account.spec.ts b/test/account.spec.ts
index 2548fbfa..2691502f 100644
--- a/test/account.spec.ts
+++ b/test/account.spec.ts
@@ -170,7 +170,7 @@ describe('Account', function() {
         nonce: '0x01',
         balance: '0x0042',
         stateRoot: '0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421',
-        codeHash: '0xc5d2461236f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470',
+        codeHash: '0xd748bf26ab37599c944babfdbeecf6690801bd61bf2670efb0a34adfc6dca10b',
       }
       const account = Account.fromAccountData(raw)
       assert.equal(account.isEmpty(), false)

From 69a5ef403663599b9ddadb83fb4853118adaecc1 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Tue, 29 Sep 2020 12:58:37 -0700
Subject: [PATCH 09/11] move `bnToRlp` to types file so it can be exported in
 the main package for use in monorepo

---
 src/account.ts |  4 ++--
 src/helpers.ts | 12 ------------
 src/types.ts   | 11 +++++++++++
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/src/account.ts b/src/account.ts
index b057b93a..1cc691d7 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -5,8 +5,8 @@ import { stripHexPrefix } from 'ethjs-util'
 import { KECCAK256_RLP, KECCAK256_NULL } from './constants'
 import { zeros, bufferToHex, toBuffer } from './bytes'
 import { keccak, keccak256, keccakFromString, rlphash } from './hash'
-import { assertIsHexString, assertIsBuffer, bnToRlp } from './helpers'
-import { BNLike, BufferLike } from './types'
+import { assertIsHexString, assertIsBuffer } from './helpers'
+import { BNLike, BufferLike, bnToRlp } from './types'
 
 const {
   privateKeyVerify,
diff --git a/src/helpers.ts b/src/helpers.ts
index bcceaa22..3fd4eacd 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -1,6 +1,4 @@
-import * as BN from 'bn.js'
 import { isHexString } from 'ethjs-util'
-import { unpadBuffer } from './bytes'
 
 /**
  * Throws if a string is not hex prefixed
@@ -45,13 +43,3 @@ export const assertIsString = function(input: string): void {
     throw new Error(msg)
   }
 }
-
-/**
- * Convert value from BN to RLP (unpadded buffer)
- * @param value value to convert
- */
-export function bnToRlp(value: BN): Buffer {
-  // Using `bn.toArrayLike(Buffer)` instead of `bn.toBuffer()`
-  // for compatibility with browserify and similar tools
-  return unpadBuffer(value.toArrayLike(Buffer))
-}
diff --git a/src/types.ts b/src/types.ts
index 894c9133..6cb819b4 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,4 +1,5 @@
 import * as BN from 'bn.js'
+import { unpadBuffer } from './bytes'
 
 export type BNLike = BN | string | number
 
@@ -9,3 +10,13 @@ export type PrefixedHexString = string
 export interface TransformableToBuffer {
   toBuffer(): Buffer
 }
+
+/**
+ * Convert value from BN to RLP (unpadded buffer)
+ * @param value value to convert
+ */
+export function bnToRlp(value: BN): Buffer {
+  // Using `bn.toArrayLike(Buffer)` instead of `bn.toBuffer()`
+  // for compatibility with browserify and similar tools
+  return unpadBuffer(value.toArrayLike(Buffer))
+}

From b0aacc0eff2ded594a12b614508a294ad9c63f4b Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Wed, 30 Sep 2020 09:37:52 -0700
Subject: [PATCH 10/11] add validation for nonce and balance

---
 src/account.ts       | 26 ++++++++++++++++++--------
 test/account.spec.ts | 12 ++++++++++++
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/src/account.ts b/src/account.ts
index 1cc691d7..e7cbb349 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -61,7 +61,7 @@ export class Account {
   }
 
   /**
-   * This constructor takes the values, validates and assigns them.
+   * This constructor assigns and validates the values.
    * Use the static factory methods to assist in creating an Account from varying data types.
    */
   constructor(
@@ -70,17 +70,27 @@ export class Account {
     stateRoot = KECCAK256_RLP,
     codeHash = KECCAK256_NULL,
   ) {
-    if (stateRoot.length !== 32) {
-      throw new Error('stateRoot must have a length of 32')
-    }
-    if (codeHash.length !== 32) {
-      throw new Error('codeHash must have a length of 32')
-    }
-
     this.nonce = nonce
     this.balance = balance
     this.stateRoot = stateRoot
     this.codeHash = codeHash
+
+    this._validate()
+  }
+
+  private _validate() {
+    if (this.nonce.lt(new BN(0))) {
+      throw new Error('nonce must be greater than zero')
+    }
+    if (this.balance.lt(new BN(0))) {
+      throw new Error('balance must be greater than zero')
+    }
+    if (this.stateRoot.length !== 32) {
+      throw new Error('stateRoot must have a length of 32')
+    }
+    if (this.codeHash.length !== 32) {
+      throw new Error('codeHash must have a length of 32')
+    }
   }
 
   /**
diff --git a/test/account.spec.ts b/test/account.spec.ts
index 2691502f..c999b357 100644
--- a/test/account.spec.ts
+++ b/test/account.spec.ts
@@ -196,6 +196,18 @@ describe('Account', function() {
         Account.fromRlpSerializedAccount(data as any)
       })
     })
+
+    it('should not accept nonce less than 0', function() {
+      assert.throws(() => {
+        new Account(new BN(-5))
+      })
+    })
+
+    it('should not accept balance less than 0', function() {
+      assert.throws(() => {
+        new Account(undefined, new BN(-5))
+      })
+    })
   })
 })
 

From e48478d3449fed6142cd6f611dffab5d4ed46ee3 Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Wed, 30 Sep 2020 10:22:44 -0700
Subject: [PATCH 11/11] more docs, fixups

---
 src/account.ts |  8 +++++---
 src/types.ts   | 21 ++++++++++++++++++++-
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/account.ts b/src/account.ts
index e7cbb349..e3d2c6df 100644
--- a/src/account.ts
+++ b/src/account.ts
@@ -109,6 +109,8 @@ export class Account {
 
   /**
    * Returns a `Boolean` determining if the account is empty.
+   * For more details about account emptiness see [EIP-161](https://eips.ethereum.org/EIPS/eip-161).
+   * Note: The stateRoot is also checked to be empty since in Frontier it was possible to create a contract with no code where nonce remained 0 but some values were written to storage in the constructor (thus stateRoot is not KECCAK256_RLP).
    */
   isEmpty(): boolean {
     return (
@@ -133,7 +135,7 @@ export const isValidAddress = function(hexAddress: string): boolean {
  *
  * If a eip1191ChainId is provided, the chainId will be included in the checksum calculation. This
  * has the effect of checksummed addresses for one chain having invalid checksums for others.
- * For more details, consult EIP-1191.
+ * For more details see [EIP-1191](https://eips.ethereum.org/EIPS/eip-1191).
  *
  * WARNING: Checksums with and without the chainId will differ. As of 2019-06-26, the most commonly
  * used variation in Ethereum was without the chainId. This may change in the future.
@@ -285,7 +287,7 @@ export const importPublic = function(publicKey: Buffer): Buffer {
 }
 
 /**
- * Returns a zero address.
+ * Returns the zero address.
  */
 export const zeroAddress = function(): string {
   const addressLength = 20
@@ -294,7 +296,7 @@ export const zeroAddress = function(): string {
 }
 
 /**
- * Checks if a given address is a zero address.
+ * Checks if a given address is the zero address.
  */
 export const isZeroAddress = function(hexAddress: string): boolean {
   assertIsHexString(hexAddress)
diff --git a/src/types.ts b/src/types.ts
index 6cb819b4..64ec1a35 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,12 +1,31 @@
 import * as BN from 'bn.js'
 import { unpadBuffer } from './bytes'
 
+/*
+ * A type that represents a BNLike input that can be converted to a BN.
+ */
 export type BNLike = BN | string | number
 
-export type BufferLike = Buffer | TransformableToBuffer | PrefixedHexString | number
+/*
+ * A type that represents a BufferLike input that can be converted to a Buffer.
+ */
+export type BufferLike =
+  | Buffer
+  | Uint8Array
+  | number[]
+  | number
+  | BN
+  | TransformableToBuffer
+  | PrefixedHexString
 
+/*
+ * A type that represents a `0x`-prefixed hex string.
+ */
 export type PrefixedHexString = string
 
+/*
+ * A type that represents an object that has a `toBuffer()` method.
+ */
 export interface TransformableToBuffer {
   toBuffer(): Buffer
 }