feat(config/eslint): provide React-specific configuration

The existing configuration attempts to auto-detect whether React-specific configurations should be loaded, however this detection does not work properly in monorepos. This provides 'eslint-react' which unconditionally loads React-specific configurations.

Author: jrolfs

eslint-react.js

@@ -0,0 +1 @@
+module.exports = require('./dist/config/eslintrc-react')

src/config/__tests__/umbrella.js

@@ -2,6 +2,7 @@ test('requiring some files does not blow up', () => {
   require('../babel-transform')
   require('../babelrc')
   require('../eslintrc')
+  require('../eslintrc-react')
   require('../jest.config')
   require('../lintstagedrc')
   require('../prettierrc')

src/config/eslintrc-react.js

@@ -0,0 +1,3 @@
+const {buildConfig} = require('./helpers/eslint')
+
+module.exports = buildConfig({withReact: true})

src/config/eslintrc.js

@@ -1,44 +1,3 @@
-const {rules} = require('eslint-config-airbnb-typescript/lib/shared')
+const {buildConfig} = require('./helpers/eslint')
 
-const {ifAnyDep} = require('../utils')
-const {testMatch} = require('./jest.config')
-
-const withBaseConfig = base => variant =>
-  require.resolve(base + (variant ? `/${variant}` : ''))
-
-const airbnb = withBaseConfig('eslint-config-airbnb-typescript')
-const prettier = withBaseConfig('eslint-config-prettier')
-
-module.exports = {
-  plugins: ['prettier', 'jest', ifAnyDep('react', 'react-hooks')].filter(
-    Boolean,
-  ),
-  extends: [
-    ifAnyDep('react', airbnb(), airbnb('base')),
-    'plugin:jest/recommended',
-    prettier(),
-    prettier('@typescript-eslint'),
-    ifAnyDep('react', prettier('react')),
-  ].filter(Boolean),
-  rules: {
-    'prettier/prettier': 'error',
-    'import/prefer-default-export': 'off',
-    'import/no-extraneous-dependencies': [
-      'error',
-      {
-        devDependencies: rules[
-          'import/no-extraneous-dependencies'
-        ][1].devDependencies.concat('jest/**'),
-        optionalDependencies: false,
-      },
-    ],
-  },
-  overrides: [
-    {
-      files: testMatch,
-      rules: {
-        'no-empty': ['error', {allowEmptyCatch: true}],
-      },
-    },
-  ],
-}
+module.exports = buildConfig()

src/config/helpers/eslint.js

@@ -0,0 +1,50 @@
+const {rules} = require('eslint-config-airbnb-typescript/lib/shared')
+
+const {hasAnyDep} = require('../../utils')
+const {testMatch} = require('../jest.config')
+
+const withBaseConfig = base => variant =>
+  require.resolve(base + (variant ? `/${variant}` : ''))
+
+const airbnb = withBaseConfig('eslint-config-airbnb-typescript')
+const prettier = withBaseConfig('eslint-config-prettier')
+
+const hasReact = hasAnyDep('react')
+
+const buildConfig = ({withReact = false} = {}) => {
+  const ifReact = (t, f) => (withReact || hasReact ? t : f)
+
+  return {
+    plugins: ['prettier', 'jest', ifReact('react-hooks')].filter(Boolean),
+    extends: [
+      ifReact(airbnb(), airbnb('base')),
+      'plugin:jest/recommended',
+      prettier(),
+      prettier('@typescript-eslint'),
+      ifReact(prettier('react')),
+    ].filter(Boolean),
+    rules: {
+      'prettier/prettier': 'error',
+      'import/prefer-default-export': 'off',
+      'import/no-extraneous-dependencies': [
+        'error',
+        {
+          devDependencies: rules[
+            'import/no-extraneous-dependencies'
+          ][1].devDependencies.concat('jest/**'),
+          optionalDependencies: false,
+        },
+      ],
+    },
+    overrides: [
+      {
+        files: testMatch,
+        rules: {
+          'no-empty': ['error', {allowEmptyCatch: true}],
+        },
+      },
+    ],
+  }
+}
+
+module.exports = {buildConfig}