Autoprefixer's browsers option is currently hardcoded. This PR adds the browserslist key in package.json which allows developers to set browsers list in queries like "Chrome >= 35", "Firefox >= 38" for both production and development. Autoprefixer which relies on Browserslist will find its config automatically. This PR fixes facebook#2248 and facebook#892

Author: cr101

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

@@ -221,12 +221,6 @@ module.exports = {
               plugins: () => [
                 require('postcss-flexbugs-fixes'),
                 autoprefixer({
-                  browsers: [
-                    '>1%',
-                    'last 4 versions',
-                    'Firefox ESR',
-                    'not ie < 9', // React doesn't support IE8 anyway
-                  ],
                   flexbox: 'no-2009',
                 }),
               ],

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

@@ -227,12 +227,6 @@ module.exports = {
                     plugins: () => [
                       require('postcss-flexbugs-fixes'),
                       autoprefixer({
-                        browsers: [
-                          '>1%',
-                          'last 4 versions',
-                          'Firefox ESR',
-                          'not ie < 9', // React doesn't support IE8 anyway
-                        ],
                         flexbox: 'no-2009',
                       }),
                     ],

packages/react-scripts/package.json

@@ -21,7 +21,7 @@
     "react-scripts": "./bin/react-scripts.js"
   },
   "dependencies": {
-    "autoprefixer": "7.1.0",
+    "autoprefixer": "7.1.1",
     "babel-core": "6.24.1",
     "babel-eslint": "7.2.3",
     "babel-jest": "20.0.3",

packages/react-scripts/scripts/init.js

@@ -49,6 +49,11 @@ module.exports = function(
     eject: 'react-scripts eject',
   };
 
+  appPackage.browserslist = {
+    production: ['> 1%', 'last 4 versions', 'Firefox ESR', 'not ie < 9'],
+    development: ['last 1 version'],
+  };
+
   fs.writeFileSync(
     path.join(appPath, 'package.json'),
     JSON.stringify(appPackage, null, 2)