facebook#9739 Set proxy setting from environment variables, falling back to package.json

Author: wozzo

packages/react-scripts/scripts/start.js

@@ -126,7 +126,7 @@ checkBrowsers(paths.appPath, isInteractive)
       webpack,
     });
     // Load proxy config
-    const proxySetting = require(paths.appPackageJson).proxy;
+    const proxySetting = process.env.PROXY || require(paths.appPackageJson).proxy;
     const proxyConfig = prepareProxy(
       proxySetting,
       paths.appPublic,