Setup building, linting and testing of TypeScript (jestjs#7808)

.eslintrc.js

@@ -15,6 +15,19 @@ module.exports = {
     'prettier/flowtype',
   ],
   overrides: [
+    {
+      files: ['*.ts', '*.tsx'],
+      parser: '@typescript-eslint/parser',
+      plugins: ['@typescript-eslint/eslint-plugin'],
+      rules: {
+        '@typescript-eslint/no-unused-vars': [
+          'error',
+          {argsIgnorePattern: '^_'},
+        ],
+        'import/order': 'error',
+        'no-unused-vars': 'off',
+      },
+    },
     // to make it more suitable for running on code examples in docs/ folder
     {
       files: ['*.md'],
@@ -122,6 +135,7 @@ module.exports = {
           '^types/(.*)': './types/$1',
         },
       },
+      'eslint-import-resolver-typescript': true,
     },
   },
 };

CHANGELOG.md

@@ -6,6 +6,8 @@
 
 ### Chore & Maintenance
 
+- `[*]`: Setup building, linting and testing of TypeScript ([#7808](https://github.com/facebook/jest/pull/7808))
+
 ### Performance
 
 ## 24.1.0

babel.config.js

@@ -2,6 +2,21 @@
 
 module.exports = {
   babelrcRoots: ['examples/*'],
+  overrides: [
+    {
+      presets: ['@babel/preset-flow'],
+      test: '**/*.js',
+    },
+    {
+      plugins: [
+        require.resolve(
+          './scripts/babel-plugin-jest-replace-ts-export-assignment.js'
+        ),
+      ],
+      presets: ['@babel/preset-typescript'],
+      test: /\.tsx?$/,
+    },
+  ],
   plugins: [
     ['@babel/plugin-transform-modules-commonjs', {allowTopLevelThis: true}],
     '@babel/plugin-transform-strict-mode',
@@ -14,6 +29,5 @@ module.exports = {
         targets: {node: 6},
       },
     ],
-    '@babel/preset-flow',
   ],
 };