Fix bypass proxy middleware

The `bypass` feature was no longer working because the code added the bypass method as middleware AND `httpProxyMiddleware` as middleware. However, if a `bypass` method is given, it should only use that as middleware.

This was caused in #359, and effects `1.15.0` and the 2.x branch.

Author: SpaceK33z

lib/Server.js

@@ -169,19 +169,24 @@ function Server(compiler, options) {
 				 * ]
 				 */
 				options.proxy.forEach(function(proxyConfig) {
+					var bypass = typeof proxyConfig.bypass === 'function';
 					var context = proxyConfig.context || proxyConfig.path;
 
-					app.use(function(req, res, next) {
-						if(typeof proxyConfig.bypass === 'function') {
-							var bypassUrl = proxyConfig.bypass(req, res, proxyConfig) || false;
+					function bypassMiddleware(req, res, next) {
+						var bypassUrl = proxyConfig.bypass(req, res, proxyConfig) || false;
 
-							if(bypassUrl) {
-								req.url = bypassUrl;
-							}
+						if(bypassUrl) {
+							req.url = bypassUrl;
 						}
 
 						next();
-					}, httpProxyMiddleware(context, proxyConfig));
+					}
+
+					if(bypass) {
+						app.use(bypassMiddleware);
+					} else {
+						app.use(httpProxyMiddleware(context, proxyConfig));
+					}
 				});
 			}
 		},