Use TypeScript; update deps; refactor exports

.eslintrc.js

@@ -10,10 +10,42 @@ module.exports = {
     },
 
     {
-      files: ['*.test.js'],
+      files: ['*.ts'],
+      extends: ['@metamask/eslint-config-typescript'],
+      // TODO: Migrate to our shared config
+      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'],
     },
   ],
 
   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

@@ -3,7 +3,9 @@
  * https://jestjs.io/docs/configuration
  */
 
-module.exports = {
+import type { Config } from '@jest/types';
+
+const config: Config.InitialOptions = {
   // All imported modules in your tests should be mocked automatically
   // automock: false,
 
@@ -22,7 +24,7 @@ module.exports = {
   collectCoverage: true,
 
   // An array of glob patterns indicating a set of files for which coverage information should be collected
-  collectCoverageFrom: ['./src/**/*.js'],
+  collectCoverageFrom: ['./src/**/*.ts'],
 
   // The directory where Jest should output its coverage files
   coverageDirectory: 'coverage',
@@ -39,6 +41,7 @@ module.exports = {
   coverageReporters: ['text', 'html'],
 
   // An object that configures minimum threshold enforcement for coverage results
+  // TODO: Fix lack of coverage and restore to 100%
   coverageThreshold: {
     global: {
       branches: 80,
@@ -97,7 +100,7 @@ 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,
@@ -202,3 +205,5 @@ module.exports = {
   // Whether to use watchman for file crawling
   // watchman: true,
 };
+
+export default config;

package.json

@@ -7,12 +7,13 @@
     "url": "https://github.com/MetaMask/eth-json-rpc-infura.git"
   },
   "license": "ISC",
-  "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",
@@ -24,9 +25,9 @@
     "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": "^2.6.7"
   },
   "devDependencies": {
@@ -35,8 +36,15 @@
     "@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",
@@ -45,7 +53,11 @@
     "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"
@@ -57,8 +69,8 @@
   "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,
+    );
+  });
+});