chore: port lowercase-name to TypeScript (#258)

Author: SimenB

.eslintrc.js

@@ -3,13 +3,14 @@
 const { globals } = require('./').environments.globals;
 
 module.exports = {
+  parser: '@typescript-eslint/parser',
   extends: [
-    'eslint:recommended',
     'plugin:eslint-plugin/recommended',
     'plugin:node/recommended',
+    'plugin:@typescript-eslint/eslintRecommended',
     'prettier',
   ],
-  plugins: ['eslint-plugin', 'node', 'prettier'],
+  plugins: ['eslint-plugin', 'node', 'prettier', '@typescript-eslint'],
   parserOptions: {
     ecmaVersion: 2017,
   },
@@ -37,8 +38,14 @@ module.exports = {
   },
   overrides: [
     {
-      files: ['*.test.js'],
+      files: ['*.test.js', '*.test.ts'],
       globals,
     },
+    {
+      files: ['*.ts'],
+      parserOptions: {
+        sourceType: 'module',
+      },
+    },
   ],
 };

.travis.yml

@@ -14,6 +14,7 @@ script:
 - yarn commitlint --from="$TRAVIS_BRANCH" --to="$TRAVIS_COMMIT"
 - yarn commitlint --from=$TRAVIS_COMMIT
 - yarn prettylint
+- yarn typecheck
 - yarn test --coverage --maxWorkers 2
 after_script: greenkeeper-lockfile-upload
 jobs:

babel.config.js

@@ -1,5 +1,8 @@
 'use strict';
 
 module.exports = {
-  presets: [['@babel/preset-env', { targets: { node: 6 } }]],
+  presets: [
+    '@babel/preset-typescript',
+    ['@babel/preset-env', { targets: { node: 6 } }],
+  ],
 };

package.json

@@ -28,18 +28,25 @@
   },
   "scripts": {
     "postinstall": "yarn build",
-    "lint": "eslint . --ignore-pattern '!.eslintrc.js'",
+    "lint": "eslint . --ignore-pattern '!.eslintrc.js' --ext js,ts",
     "prettylint": "prettylint docs/**/*.md README.md package.json",
     "prepublishOnly": "yarn build",
     "test": "jest",
-    "build": "babel src --out-dir lib"
+    "build": "babel --extensions .js,.ts src --out-dir lib",
+    "typecheck": "tsc -p ."
   },
   "devDependencies": {
     "@babel/cli": "^7.4.4",
     "@babel/core": "^7.4.4",
     "@babel/preset-env": "^7.4.4",
+    "@babel/preset-typescript": "^7.3.3",
     "@commitlint/cli": "^7.0.0",
     "@commitlint/config-conventional": "^7.0.1",
+    "@types/eslint": "^4.16.6",
+    "@types/jest": "^24.0.12",
+    "@types/node": "^12.0.0",
+    "@typescript-eslint/eslint-plugin": "^1.8.0",
+    "@typescript-eslint/experimental-utils": "^1.8.0",
     "babel-jest": "^24.8.0",
     "eslint": "^5.1.0",
     "eslint-config-prettier": "^4.1.0",
@@ -51,15 +58,16 @@
     "jest-runner-eslint": "^0.7.1",
     "lint-staged": "^8.0.4",
     "prettier": "^1.10.2",
-    "prettylint": "^1.0.0"
+    "prettylint": "^1.0.0",
+    "typescript": "^3.4.5"
   },
   "prettier": {
     "proseWrap": "always",
     "singleQuote": true,
     "trailingComma": "all"
   },
   "lint-staged": {
-    "*.js": [
+    "*.{js,ts}": [
       "eslint --fix",
       "git add"
     ],

src/index.js

@@ -3,12 +3,26 @@
 const fs = require('fs');
 const path = require('path');
 
+// copied from https://github.com/babel/babel/blob/56044c7851d583d498f919e9546caddf8f80a72f/packages/babel-helpers/src/helpers.js#L558-L562
+function interopRequireDefault(obj) {
+  return obj && obj.__esModule ? obj : { default: obj };
+}
+
 const rules = fs
   .readdirSync(path.join(__dirname, 'rules'))
-  .filter(rule => rule !== '__tests__' && rule !== 'util.js')
-  .map(rule => path.basename(rule, '.js'))
+  .filter(
+    rule => rule !== '__tests__' && rule !== 'util.js' && rule !== 'tsUtils.ts',
+  )
+  .map(rule =>
+    rule.endsWith('js')
+      ? path.basename(rule, '.js')
+      : path.basename(rule, '.ts'),
+  )
   .reduce(
-    (acc, curr) => Object.assign(acc, { [curr]: require(`./rules/${curr}`) }),
+    (acc, curr) => ({
+      ...acc,
+      [curr]: interopRequireDefault(require(`./rules/${curr}`)).default,
+    }),
     {},
   );
 

src/rules/__tests__/lowercase-name.test.js renamed to src/rules/__tests__/lowercase-name.test.ts

@@ -1,16 +1,20 @@
-'use strict';
+import { RuleTester as ESLintRuleTester } from 'eslint';
+import { TSESLint } from '@typescript-eslint/experimental-utils';
+import rule from '../lowercase-name';
 
-const { RuleTester } = require('eslint');
-const rule = require('../lowercase-name');
+const RuleTester: TSESLint.RuleTester = ESLintRuleTester as any;
 
 const ruleTester = new RuleTester({
+  parser: '@typescript-eslint/parser',
   parserOptions: {
     ecmaVersion: 6,
   },
 });
 
 ruleTester.run('lowercase-name', rule, {
   valid: [
+    'randomFunction()',
+    'foo.bar()',
     'it()',
     "it(' ', function () {})",
     'it(" ", function () {})',
@@ -22,6 +26,8 @@ ruleTester.run('lowercase-name', rule, {
     'it("123 foo", function () {})',
     'it(42, function () {})',
     'it(``)',
+    'it("")',
+    'it(42)',
     'test()',
     "test('foo', function () {})",
     'test("foo", function () {})',
@@ -30,6 +36,8 @@ ruleTester.run('lowercase-name', rule, {
     'test("123 foo", function () {})',
     'test("42", function () {})',
     'test(``)',
+    'test("")',
+    'test(42)',
     'describe()',
     "describe('foo', function () {})",
     'describe("foo", function () {})',
@@ -39,6 +47,8 @@ ruleTester.run('lowercase-name', rule, {
     'describe("42", function () {})',
     'describe(function () {})',
     'describe(``)',
+    'describe("")',
+    'describe(42)',
   ],
 
   invalid: [
@@ -47,7 +57,8 @@ ruleTester.run('lowercase-name', rule, {
       output: "it('foo', function () {})",
       errors: [
         {
-          message: '`it`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'it' },
           column: 1,
           line: 1,
         },
@@ -58,7 +69,8 @@ ruleTester.run('lowercase-name', rule, {
       output: 'it("foo", function () {})',
       errors: [
         {
-          message: '`it`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'it' },
           column: 1,
           line: 1,
         },
@@ -69,7 +81,8 @@ ruleTester.run('lowercase-name', rule, {
       output: 'it(`foo`, function () {})',
       errors: [
         {
-          message: '`it`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'it' },
           column: 1,
           line: 1,
         },
@@ -80,7 +93,8 @@ ruleTester.run('lowercase-name', rule, {
       output: "test('foo', function () {})",
       errors: [
         {
-          message: '`test`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'test' },
           column: 1,
           line: 1,
         },
@@ -91,7 +105,8 @@ ruleTester.run('lowercase-name', rule, {
       output: 'test("foo", function () {})',
       errors: [
         {
-          message: '`test`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'test' },
           column: 1,
           line: 1,
         },
@@ -102,7 +117,8 @@ ruleTester.run('lowercase-name', rule, {
       output: 'test(`foo`, function () {})',
       errors: [
         {
-          message: '`test`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'test' },
           column: 1,
           line: 1,
         },
@@ -113,7 +129,8 @@ ruleTester.run('lowercase-name', rule, {
       output: "describe('foo', function () {})",
       errors: [
         {
-          message: '`describe`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'describe' },
           column: 1,
           line: 1,
         },
@@ -124,7 +141,8 @@ ruleTester.run('lowercase-name', rule, {
       output: 'describe("foo", function () {})',
       errors: [
         {
-          message: '`describe`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'describe' },
           column: 1,
           line: 1,
         },
@@ -135,7 +153,8 @@ ruleTester.run('lowercase-name', rule, {
       output: 'describe(`foo`, function () {})',
       errors: [
         {
-          message: '`describe`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'describe' },
           column: 1,
           line: 1,
         },
@@ -146,7 +165,8 @@ ruleTester.run('lowercase-name', rule, {
       output: 'describe(`some longer description`, function () {})',
       errors: [
         {
-          message: '`describe`s should begin with lowercase',
+          messageId: 'unexpectedLowercase',
+          data: { method: 'describe' },
           column: 1,
           line: 1,
         },