chore: initialise repository for TypeScript

Author: jdbruijn

.eslintrc.js

@@ -9,6 +9,27 @@ const defaultConfig = {
     node: true,
   },
   rules: {
+    'no-restricted-globals': [
+      'error',
+      /**
+       * From Jest global environment.
+       * https://github.com/facebook/jest/blob/v26.4.2/packages/jest-globals/src/index.ts#L12-L27
+       */
+      'jest',
+      'expect',
+      'it',
+      'test',
+      'fit',
+      'xit',
+      'xtest',
+      'describe',
+      'xdescribe',
+      'fdescribe',
+      'beforeAll',
+      'beforeEach',
+      'afterEach',
+      'afterAll',
+    ],
     'prettier/prettier': 'error',
     'sort-imports': 'error',
   },
@@ -42,6 +63,17 @@ function addToDefaultExtends(...configurations) {
 
 const config = defaultConfig;
 config.overrides = [
+  {
+    files: ['**/*.ts', '**/*.tsx'],
+    extends: addToDefaultExtends(
+      'plugin:@typescript-eslint/recommended',
+      'prettier/@typescript-eslint',
+      'plugin:jest/style',
+    ),
+    parser: '@typescript-eslint/parser',
+    plugins: defaultConfig.plugins.concat(['@typescript-eslint']),
+    rules: { ...defaultConfig.rules, 'jest/consistent-test-it': 'error' },
+  },
   {
     files: ['**/*.json'],
     extends: addToDefaultExtends('plugin:json/recommended'),

.lintstagedrc.js

@@ -1,5 +1,9 @@
 module.exports = {
-  '*.{ts,tsx,js,jsx,json}': ['npm run format:file', 'npm run lint-es:file:fix'],
+  '*.{ts,tsx,js,jsx,json}': [
+    'npm run format:file',
+    'npm run lint-es:file:fix',
+    'npm run test:staged',
+  ],
   '*.{vue,css,less,scss,html,htm,md,markdown,yml,yaml}': [
     'npm run format:file',
   ],

jest.config.js

@@ -0,0 +1,8 @@
+module.exports = {
+  collectCoverage: true,
+  collectCoverageFrom: ['src/**/*.ts'],
+  coverageDirectory: 'coverage',
+  coverageReporters: ['cobertura', 'lcov', 'text'],
+  preset: 'ts-jest',
+  roots: ['<rootDir>/src'],
+};