feat: type checking & type generation

.eslintrc

@@ -0,0 +1,13 @@
+{
+  "extends": [
+    "standard",
+    "plugin:@typescript-eslint/recommended"
+  ],
+  "plugins": [
+    "@typescript-eslint"
+  ],
+  "rules": {
+    "@typescript-eslint/explicit-module-boundary-types": "off",
+    "@typescript-eslint/ban-ts-comment": "off"
+  }
+}

.github/workflows/typecheck.yml

@@ -0,0 +1,27 @@
+on:
+  push:
+    branches:
+      - master
+      - main
+      - default
+  pull_request:
+    branches:
+      - '**'
+
+name: Typecheck
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [12.x]
+    steps:
+      - uses: actions/checkout@v1
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Install dependencies
+        run: npm install
+      - name: Typecheck
+        uses: gozala/[email protected]

package.json

@@ -5,13 +5,16 @@
   "main": "index.js",
   "type": "module",
   "scripts": {
-    "build": "npm_config_yes=true npx ipjs@latest build --tests",
+    "build": "npm run build:js && npm run build:types",
+    "build:js": "npm_config_yes=true npx ipjs@latest build --tests",
+    "build:types": "tsc --emitDeclarationOnly --declarationDir dist/types",
     "build:vendor": "npm run build:vendor:varint && npm run build:vendor:base-x",
     "build:vendor:varint": "npx brrp -x varint > vendor/varint.js",
     "build:vendor:base-x": "npx brrp -x @multiformats/base-x > vendor/base-x.js",
     "publish": "npm_config_yes=true npx ipjs@latest publish",
     "lint": "standard",
-    "test:cjs": "npm run build && mocha dist/cjs/node-test/test-*.js && npm run test:cjs:browser",
+    "check": "tsc --noEmit --noErrorTruncation",
+    "test:cjs": "npm run build:js && mocha dist/cjs/node-test/test-*.js && npm run test:cjs:browser",
     "test:node": "hundreds mocha test/test-*.js",
     "test:cjs:browser": "polendina --cleanup dist/cjs/browser-test/test-*.js",
     "test": "npm run lint && npm run test:node && npm run test:cjs",
@@ -78,11 +81,16 @@
     "hundreds": "0.0.7",
     "mocha": "^8.1.1",
     "polendina": "^1.0.0",
-    "standard": "^14.3.4"
+    "standard": "^14.3.4",
+    "typescript": "^4.0.3",
+    "@types/node": "14.11.7",
+    "@typescript-eslint/eslint-plugin": "^4.4.0",
+    "@typescript-eslint/parser": "^4.4.0"
   },
   "standard": {
     "ignore": [
-      "dist"
+      "dist",
+      "vendor"
     ]
   },
   "dependencies": {
@@ -100,5 +108,12 @@
   "bugs": {
     "url": "https://github.com/multiformats/js-multiformats/issues"
   },
-  "homepage": "https://github.com/multiformats/js-multiformats#readme"
+  "homepage": "https://github.com/multiformats/js-multiformats#readme",
+  "typesVersions": {
+    "*": {
+      "*": [
+        "dist/types/*"
+      ]
+    }
+  }
 }

src/bases/base.js

@@ -1,5 +1,3 @@
-// @ts-check
-
 /**
  * @typedef {import('./interface').BaseEncoder} BaseEncoder
  * @typedef {import('./interface').BaseDecoder} BaseDecoder
@@ -162,7 +160,7 @@ class ComposedDecoder {
    * @returns {Uint8Array}
    */
   decode (input) {
-    const prefix = input[0]
+    const prefix = /** @type {Prefix} */ (input[0])
     const decoder = this.decoders[prefix]
     if (decoder) {
       return decoder.decode(input)
@@ -211,6 +209,9 @@ export class Codec {
     return this.encoder.encode(input)
   }
 
+  /**
+   * @param {string} input
+   */
   decode (input) {
     return this.decoder.decode(input)
   }

src/bases/base32.js

@@ -1,7 +1,9 @@
-// @ts-check
-
 import { withAlphabet } from './base.js'
 
+/**
+ * @param {string} input
+ * @param {input} alphabet
+ */
 function decode (input, alphabet) {
   input = input.replace(new RegExp('=', 'g'), '')
   const length = input.length
@@ -25,6 +27,10 @@ function decode (input, alphabet) {
   return output
 }
 
+/**
+ * @param {Uint8Array} buffer
+ * @param {string} alphabet
+ */
 function encode (buffer, alphabet) {
   const length = buffer.byteLength
   const view = new Uint8Array(buffer)

src/bases/base58.js

@@ -1,13 +1,17 @@
-// @ts-check
-
 import baseX from '../../vendor/base-x.js'
 import { coerce } from '../bytes.js'
 import { from } from './base.js'
 
+/**
+ * @param {string} alphabet
+ */
 const implement = (alphabet) => {
   const { encode, decode } = baseX(alphabet)
   return {
     encode,
+    /**
+     * @param {string} text
+     */
     decode: text => coerce(decode(text))
   }
 }

src/bases/base64-browser.js

@@ -1,10 +1,8 @@
-// @ts-check
-
 /* globals btoa, atob */
 import b64 from './base64.js'
 
 const { base64, base64pad, base64url, base64urlpad, __browser } = b64({
-  encode: b => btoa([].reduce.call(b, (p, c) => p + String.fromCharCode(c), '')),
+  encode: b => btoa(b.reduce((p, c) => p + String.fromCharCode(c), '')),
   decode: str => Uint8Array.from(atob(str), c => c.charCodeAt(0)),
   __browser: true
 })