TypeChain

🔌 TypeScript bindings for Ethereum smartcontracts

Medium post | DappCon Video

Contributed with:

Features ⚡

• static typing - you will never call not existing method again
• IDE support - works with any IDE supporting Typescript
• extendible - work with many different APIs: ethers.js v4, truffle v4 , truffle v5, Web3.js v1, Web3.js v2 or you can create your own target
• frictionless - works with simple, JSON ABI files as well as with Truffle style ABIs

Installation

npm install --save-dev typechain

You will also need to install a desired target for example typechain-target-ethers. Learn more about targets

Packages 📦

Package	Version	Description	Examples
typechain		Core package	-
@typechain/ethers-v4		Ethers ver 4 support	example
@typechain/truffle-v4		Truffle ver 4 support	example
@typechain/truffle-v5		Truffle ver 5 support	example
@typechain/web3-v1		Web3 ver 1 support	example

Usage

CLI

typechain --target=(ethers-v4|truffle-v4|truffle-v5|web3-v1|path-to-custom-target) [glob]

• glob - pattern that will be used to find ABIs, remember about adding quotes: typechain "**/*.json", examples: ./abis/**/*.abi, ./abis/?(Oasis.abi|OasisHelper.abi).
• --target - ethers-v4, truffle-v4, truffle-v5, web3-v1 or path to your custom target. Typechain will try to load package named. typechain-target-${target}, so make sure that desired package is installed.
• --outDir (optional) - put all generated files to a specific dir.

TypeChain always will rewrite existing files. You should not commit them. Read more in FAQ section.

Example:

typechain --target ethers-v4 --outDir app/contracts './node_modules/neufund-contracts/build/contracts/*.json'

Demo 🏎️

Example usage

Getting started 📚

Motivation

Interacting with blockchain in Javascript is a pain. Web3 interface is sluggish and when using it with Typescript it gets even worse. Often, you can't be sure what given method call will actually do without looking at ABI file. TypeChain is here to solve these problems (as long as you use Typescript).

How does it work?

TypeChain is code generator - provide ABI file and you will get Typescript class with flexible interface for interacting with blockchain. Depending on the target parameter it can generate typings for truffle, web3 1.0.0 or ethers.

Step by step guide

Install typechain with yarn add --dev typechain and install desired target.

Run typechain --target=your_target (you might need to make sure that it's available in your path if you installed it only locally), it will automatically find all .abi files in your project and generate Typescript classes based on them. You can specify your glob pattern: typechain --target=your_target "**/*.abi.json". node_modules are always ignored. We recommend git ignoring these generated files and making typechain part of your build process.

That's it! Now, you can simply import typings, check out our examples for more details.

Targets 🎯

Ethers.js v4

Use ethers-v4 target to generate wrappers for ethers.js lib.

Truffle v4-v5

Truffle target is great when you use truffle contracts already. Check out truffle-typechain-example for more details. It require installing typings for truffle library itself.

Now you can simply use your contracts as you did before and get full type safety, yay!

Web3 v1

Generates typings for contracts compatible with latest stable Web3.js version. Typings for library itself are now part of the Web3 1.0.0 library so nothing additional is needed. For now it needs explicit cast as shown here, this will be fixed after improving official typings.

NatSpec support

If you provide solidity artifacts rather than plain ABIs as an input, TypeChain can generate NatSpec comments directly to your typings which enables simple access to docs while coding.

Your own target

This might be useful when you're creating a library for users of your smartcontract and you don't want to lock yourself into any API provided by Web3 access providing library. You can generate basically any code (even for different languages than TypeScript!) that based on smartcontract's ABI.

FAQ 🤔

Q: Should I commit generated files to my repository?

A: NO — we believe that no generated files should go to git repository. You should git ignore them and make typechain run automatically for example in post install hook in package.json:

"postinstall":"typechain"

When you update ABI, just regenerate files with TypeChain and Typescript compiler will find any breaking changes for you.

Q: How do I customize generated code?

A: You can create your own target and generate basically any code.

Q: Generated files won't match current codestyle of my project :(

A: We will automatically format generated classes with prettier to match your coding preferences (just make sure to use .prettierrc file).

Furthermore, we will silent tslint for generated files with /* tslint:disable */ comments.

Usage as API

You may want to use ts-generator api to kick off whole process by api:

import { tsGenerator } from 'ts-generator'
import { TypeChain } from 'typechain/dist/TypeChain'

async function main() {
  const cwd = process.cwd()

  await tsGenerator(
    { cwd },
    new TypeChain({
      cwd,
      rawConfig: {
        files: 'your-glob-here',
        outDir: 'optional out dir path',
        target: 'your-target',
      },
    }),
  )
}

main().catch(console.error)

Running tests

yarn           # install all dependencies
yarn test      # runs tests + linting
yarn test:fix  # autofix any errors + run tests

Debugging 🐞

DEBUG=typechain typechain

Licence

Krzysztof Kaczor (krzkaczor) MIT | Github | Twitter