Drop support for advanced proxy

packages/react-dev-utils/WebpackDevServerUtils.js

@@ -274,19 +274,15 @@ function prepareProxy(proxy, appPublicFolder) {
   if (!proxy) {
     return undefined;
   }
-  if (typeof proxy !== 'object' && typeof proxy !== 'string') {
+  if (typeof proxy !== 'string') {
     console.log(
-      chalk.red(
-        'When specified, "proxy" in package.json must be a string or an object.'
-      )
+      chalk.red('When specified, "proxy" in package.json must be a string.')
     );
     console.log(
       chalk.red('Instead, the type of "proxy" was "' + typeof proxy + '".')
     );
     console.log(
-      chalk.red(
-        'Either remove "proxy" from package.json, or make it an object.'
-      )
+      chalk.red('Either remove "proxy" from package.json, or make it a string.')
     );
     process.exit(1);
   }
@@ -297,82 +293,42 @@ function prepareProxy(proxy, appPublicFolder) {
     return !fs.existsSync(maybePublicPath);
   }
 
-  // Support proxy as a string for those who are using the simple proxy option
-  if (typeof proxy === 'string') {
-    if (!/^http(s)?:\/\//.test(proxy)) {
-      console.log(
-        chalk.red(
-          'When "proxy" is specified in package.json it must start with either http:// or https://'
-        )
-      );
-      process.exit(1);
-    }
-
-    let target;
-    if (process.platform === 'win32') {
-      target = resolveLoopback(proxy);
-    } else {
-      target = proxy;
-    }
-    return [
-      {
-        target,
-        logLevel: 'silent',
-        // For single page apps, we generally want to fallback to /index.html.
-        // However we also want to respect `proxy` for API calls.
-        // So if `proxy` is specified as a string, we need to decide which fallback to use.
-        // We use a heuristic: We want to proxy all the requests that are not meant
-        // for static assets and as all the requests for static assets will be using
-        // `GET` method, we can proxy all non-`GET` requests.
-        // For `GET` requests, if request `accept`s text/html, we pick /index.html.
-        // Modern browsers include text/html into `accept` header when navigating.
-        // However API calls like `fetch()` won’t generally accept text/html.
-        // If this heuristic doesn’t work well for you, use a custom `proxy` object.
-        context: function(pathname, req) {
-          return (
-            req.method !== 'GET' ||
-            (mayProxy(pathname) &&
-              req.headers.accept &&
-              req.headers.accept.indexOf('text/html') === -1)
-          );
-        },
-        onProxyReq: proxyReq => {
-          // Browers may send Origin headers even with same-origin
-          // requests. To prevent CORS issues, we have to change
-          // the Origin to match the target URL.
-          if (proxyReq.getHeader('origin')) {
-            proxyReq.setHeader('origin', target);
-          }
-        },
-        onError: onProxyError(target),
-        secure: false,
-        changeOrigin: true,
-        ws: true,
-        xfwd: true,
-      },
-    ];
+  if (!/^http(s)?:\/\//.test(proxy)) {
+    console.log(
+      chalk.red(
+        'When "proxy" is specified in package.json it must start with either http:// or https://'
+      )
+    );
+    process.exit(1);
   }
 
-  // Otherwise, proxy is an object so create an array of proxies to pass to webpackDevServer
-  return Object.keys(proxy).map(function(context) {
-    if (!proxy[context].hasOwnProperty('target')) {
-      console.log(
-        chalk.red(
-          'When `proxy` in package.json is as an object, each `context` object must have a ' +
-            '`target` property specified as a url string'
-        )
-      );
-      process.exit(1);
-    }
-    let target;
-    if (process.platform === 'win32') {
-      target = resolveLoopback(proxy[context].target);
-    } else {
-      target = proxy[context].target;
-    }
-    return Object.assign({}, proxy[context], {
-      context: function(pathname) {
-        return mayProxy(pathname) && pathname.match(context);
+  let target;
+  if (process.platform === 'win32') {
+    target = resolveLoopback(proxy);
+  } else {
+    target = proxy;
+  }
+  return [
+    {
+      target,
+      logLevel: 'silent',
+      // For single page apps, we generally want to fallback to /index.html.
+      // However we also want to respect `proxy` for API calls.
+      // So if `proxy` is specified as a string, we need to decide which fallback to use.
+      // We use a heuristic: We want to proxy all the requests that are not meant
+      // for static assets and as all the requests for static assets will be using
+      // `GET` method, we can proxy all non-`GET` requests.
+      // For `GET` requests, if request `accept`s text/html, we pick /index.html.
+      // Modern browsers include text/html into `accept` header when navigating.
+      // However API calls like `fetch()` won’t generally accept text/html.
+      // If this heuristic doesn’t work well for you, use a custom `proxy` object.
+      context: function(pathname, req) {
+        return (
+          req.method !== 'GET' ||
+          (mayProxy(pathname) &&
+            req.headers.accept &&
+            req.headers.accept.indexOf('text/html') === -1)
+        );
       },
       onProxyReq: proxyReq => {
         // Browers may send Origin headers even with same-origin
@@ -382,10 +338,13 @@ function prepareProxy(proxy, appPublicFolder) {
           proxyReq.setHeader('origin', target);
         }
       },
-      target,
       onError: onProxyError(target),
-    });
-  });
+      secure: false,
+      changeOrigin: true,
+      ws: true,
+      xfwd: true,
+    },
+  ];
 }
 
 function choosePort(host, defaultPort) {