eslintrc

Author: linhaobin

.eslintrc

@@ -7,7 +7,7 @@
     "es6": true
   },
   "parserOptions": {
-    "ecmaVersion": 6
+    "ecmaVersion": 9
   },
   "rules": {
     "no-console": "off",

packages/react-scripts/config/paths.js

@@ -89,6 +89,8 @@ module.exports = {
   customWebpackProdConfig: resolveApp('config/webpack.config.prod.js'),
   // rewired webpack devServer config
   customWebpackDevServerConfig: resolveApp('config/webpackDevServer.config.js'),
+  // eslintrc
+  eslintrcPath: resolveApp('.'),
 };
 
 const ownPackageJson = require('../package.json');
@@ -129,6 +131,8 @@ if (
     customWebpackDevServerConfig: resolveOwn(
       'template/config/webpackDevServer.config.js'
     ),
+    // eslintrc
+    eslintrcPath: resolveOwn('template'),
   };
 }
 // @remove-on-eject-end

packages/react-scripts/config/utils/useEslintrc.js

@@ -0,0 +1,25 @@
+// @remove-file-on-eject
+'use strict';
+const fs = require('fs');
+const path = require('path');
+const paths = require('../paths');
+
+const CONFIG_FILES = [
+  '.eslintrc.js',
+  '.eslintrc.yaml',
+  '.eslintrc.yml',
+  '.eslintrc.json',
+  '.eslintrc',
+];
+
+function existsConfigFile() {
+  return CONFIG_FILES.some(configFile => {
+    const filename = path.resolve(paths.eslintrcPath, configFile);
+
+    return fs.existsSync(filename) && fs.statSync(filename).isFile();
+  });
+}
+
+module.exports = !!(
+  existsConfigFile() || require(paths.appPackageJson).eslintConfig
+);

packages/react-scripts/config/webpack.config.dev.js

@@ -132,11 +132,15 @@ module.exports = {
               formatter: eslintFormatter,
               eslintPath: require.resolve('eslint'),
               // @remove-on-eject-begin
-              baseConfig: {
-                extends: [require.resolve('eslint-config-react-app')],
-              },
-              ignore: false,
-              useEslintrc: false,
+              ...(require('./utils/useEslintrc')
+                ? undefined
+                : {
+                    baseConfig: {
+                      extends: [require.resolve('eslint-config-react-app')],
+                    },
+                    ignore: false,
+                    useEslintrc: false,
+                  }),
               // @remove-on-eject-end
             },
             loader: require.resolve('eslint-loader'),

packages/react-scripts/template/.eslintrc

@@ -0,0 +1,3 @@
+{
+  "extends": "react-app"
+}