Use TypeScript; update deps; refactor exports

* **(BREAKING)** Change `index` so that it exports all public modules as
  named exports
* **(BREAKING)** Update all dependencies so that we get TypeScript
  versions
* Convert implementation code to TypeScript
* Convert tests to TypeScript, and add tests to ensure that the
  JavaScript-only checks still work for as much backward compatibility
  as possible
* Add a working TypeDoc configuration file in the event that we want to
  generate documentation

.eslintrc.js

@@ -16,10 +16,47 @@ module.exports = {
     },
 
     {
-      files: ['*.test.js'],
+      files: ['*.ts'],
+      extends: ['@metamask/eslint-config-typescript'],
+      // TODO: Migrate to shared config
+      settings: {
+        settings: {
+          'import/resolver': {
+            // Try resolving imports using TypeScript's module resolution
+            // algorithm, then Node's
+            typescript: {
+              alwaysTryTypes: true,
+            },
+            node: {},
+          },
+        },
+        jsdoc: {
+          mode: 'typescript',
+        },
+      },
+    },
+
+    {
+      files: ['*.test.ts', '*.test.js'],
       extends: ['@metamask/eslint-config-jest'],
+      rules: {
+        'import/unambiguous': 'off',
+      },
     },
   ],
 
   ignorePatterns: ['!.eslintrc.js', '!.prettierrc.js', 'dist/'],
+
+  settings: {
+    'import/resolver': {
+      // Try resolving imports using Node's module resolution algorithm,
+      // then TypeScript's — this allows us to import TypeScript files in
+      // JavaScript files (e.g. in tests that exercise a TypeScript module where
+      // we need to pretend we're in a JavaScript-only environment)
+      node: {},
+      typescript: {
+        alwaysTryTypes: true,
+      },
+    },
+  },
 };

.gitignore

@@ -38,6 +38,9 @@ node_modules/
 # TypeScript cache
 *.tsbuildinfo
 
+# TypeDoc docs
+typedocs/
+
 # Optional npm cache directory
 .npm
 

jest.config.js → jest.config.ts

@@ -1,9 +1,9 @@
 /*
- * For a detailed explanation regarding each configuration property, visit:
- * https://jestjs.io/docs/en/configuration.html
+ * For a detailed explanation regarding each configuration property and type check, visit:
+ * https://jestjs.io/docs/configuration
  */
 
-module.exports = {
+export default {
   // All imported modules in your tests should be mocked automatically
   // automock: false,
 
@@ -13,11 +13,11 @@ module.exports = {
   // The directory where Jest should store its cached dependency information
   // cacheDirectory: "/private/var/folders/fk/c3y07g0576j8_2s9m01pk4qw0000gn/T/jest_dx",
 
-  // Automatically clear mock calls and instances between every test
+  // Automatically clear mock calls, instances and results before every test
   clearMocks: true,
 
   // Indicates whether the coverage information should be collected while executing the test
-  // collectCoverage: false,
+  collectCoverage: true,
 
   // An array of glob patterns indicating a set of files for which coverage information should be collected
   // collectCoverageFrom: undefined,
@@ -73,10 +73,10 @@ module.exports = {
   // An array of file extensions your modules use
   // moduleFileExtensions: [
   //   "js",
-  //   "json",
   //   "jsx",
   //   "ts",
   //   "tsx",
+  //   "json",
   //   "node"
   // ],
 
@@ -93,15 +93,15 @@ module.exports = {
   // notifyMode: "failure-change",
 
   // A preset that is used as a base for Jest's configuration
-  // preset: undefined,
+  preset: 'ts-jest',
 
   // Run tests from one or more projects
   // projects: undefined,
 
   // Use this configuration option to add custom reporters to Jest
   // reporters: undefined,
 
-  // Automatically reset mock state between every test
+  // Automatically reset mock state before every test
   // resetMocks: false,
 
   // Reset the module registry before running each individual test
@@ -110,7 +110,7 @@ module.exports = {
   // A path to a custom resolver
   // resolver: undefined,
 
-  // Automatically restore mock state between every test
+  // Automatically restore mock state and implementation before every test
   // restoreMocks: false,
 
   // The root directory that Jest should scan for tests and modules within
@@ -137,7 +137,7 @@ module.exports = {
   // snapshotSerializers: [],
 
   // The test environment that will be used for testing
-  testEnvironment: 'node',
+  // testEnvironment: "jest-environment-node",
 
   // Options that will be passed to the testEnvironment
   // testEnvironmentOptions: {},
@@ -163,7 +163,7 @@ module.exports = {
   // testResultsProcessor: undefined,
 
   // This option allows use of a custom test runner
-  // testRunner: "jasmine2",
+  // testRunner: "jest-circus/runner",
 
   // This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
   // testURL: "http://localhost",

package.json

@@ -6,12 +6,13 @@
     "type": "git",
     "url": "https://github.com/MetaMask/eth-json-rpc-infura.git"
   },
-  "main": "src/index.js",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
   "files": [
-    "src/*.js"
+    "dist/"
   ],
   "scripts": {
-    "build": "echo 'nothing to build yet'",
+    "build": "tsc --project tsconfig.build.json",
     "build:clean": "rimraf dist && yarn build",
     "lint": "yarn lint:eslint && yarn lint:misc --check",
     "lint:eslint": "eslint . --cache --ext js,ts",
@@ -23,9 +24,9 @@
     "test:watch": "jest --watch"
   },
   "dependencies": {
-    "eth-json-rpc-middleware": "^6.0.0",
-    "eth-rpc-errors": "^3.0.0",
-    "json-rpc-engine": "^5.3.0",
+    "eth-json-rpc-middleware": "^8.0.1",
+    "eth-rpc-errors": "^4.0.3",
+    "json-rpc-engine": "^6.1.0",
     "node-fetch": "^2.6.1"
   },
   "devDependencies": {
@@ -34,8 +35,15 @@
     "@metamask/eslint-config": "^9.0.0",
     "@metamask/eslint-config-jest": "^9.0.0",
     "@metamask/eslint-config-nodejs": "^9.0.0",
+    "@metamask/eslint-config-typescript": "^9.0.1",
+    "@types/jest": "^26.0.13",
+    "@types/node": "^17.0.23",
+    "@types/node-fetch": "^2.6.1",
+    "@typescript-eslint/eslint-plugin": "^4.21.0",
+    "@typescript-eslint/parser": "^4.21.0",
     "eslint": "^7.23.0",
     "eslint-config-prettier": "^8.5.0",
+    "eslint-import-resolver-typescript": "^2.7.0",
     "eslint-plugin-import": "^2.25.4",
     "eslint-plugin-jest": "^24.3.4",
     "eslint-plugin-jsdoc": "^36.1.0",
@@ -44,7 +52,11 @@
     "jest": "^26.4.2",
     "prettier": "^2.6.1",
     "prettier-plugin-packagejson": "^2.2.17",
-    "rimraf": "^3.0.2"
+    "rimraf": "^3.0.2",
+    "ts-jest": "^26.3.0",
+    "ts-node": "^10.7.0",
+    "typedoc": "^0.22.13",
+    "typescript": "~4.4.0"
   },
   "engines": {
     "node": ">=12.0.0"
@@ -56,8 +68,8 @@
   "lavamoat": {
     "allowScripts": {
       "@lavamoat/preinstall-always-fail": false,
-      "eth-json-rpc-middleware>ethereumjs-util>ethereum-cryptography>keccak": true,
-      "eth-json-rpc-middleware>ethereumjs-util>ethereum-cryptography>secp256k1": true
+      "eth-json-rpc-middleware>eth-sig-util>ethereumjs-util>ethereum-cryptography>keccak": true,
+      "eth-json-rpc-middleware>eth-sig-util>ethereumjs-util>ethereum-cryptography>secp256k1": true
     }
   }
 }

src/createInfuraMiddleware.test.js

@@ -0,0 +1,39 @@
+const { createInfuraMiddleware } = require('.');
+
+describe('createInfuraMiddleware (JS-only tests)', () => {
+  it('throws when the projectId is a number', () => {
+    expect(() => createInfuraMiddleware({ projectId: 42 })).toThrow(
+      /Invalid value for 'projectId'/u,
+    );
+  });
+
+  it('throws when the projectId is undefined', () => {
+    expect(() => createInfuraMiddleware({ projectId: undefined })).toThrow(
+      /Invalid value for 'projectId'/u,
+    );
+  });
+
+  it('throws when the projectId is null', () => {
+    expect(() => createInfuraMiddleware({ projectId: null })).toThrow(
+      /Invalid value for 'projectId'/u,
+    );
+  });
+
+  it('throws when headers is null', () => {
+    expect(() =>
+      createInfuraMiddleware({ projectId: 'foo', headers: null }),
+    ).toThrow(/Invalid value for 'headers'/u);
+  });
+
+  it('throws when headers is a number', () => {
+    expect(() =>
+      createInfuraMiddleware({ projectId: 'foo', headers: 42 }),
+    ).toThrow(/Invalid value for 'headers'/u);
+  });
+
+  it('throws when headers is an empty string', () => {
+    expect(() =>
+      createInfuraMiddleware({ projectId: 'foo', headers: '' }),
+    ).toThrow(/Invalid value for 'headers'/u);
+  });
+});

src/createInfuraMiddleware.test.ts

@@ -0,0 +1,9 @@
+import { createInfuraMiddleware } from '.';
+
+describe('createInfuraMiddleware', () => {
+  it('throws when the projectId is an empty string', () => {
+    expect(() => createInfuraMiddleware({ projectId: '' })).toThrow(
+      /Invalid value for 'projectId'/u,
+    );
+  });
+});