build(serve): added cors support for the js.server task

Added and used the cors middleware:
- add the module as a dev depedency in the package.json file
- require the module in the jsserve.js file
- add the module in the middleware list

Closes #7273

Closes #7274

npm-shrinkwrap.clean.json

@@ -1831,6 +1831,9 @@
     "core-util-is": {
       "version": "1.0.2"
     },
+    "cors": {
+      "version": "2.7.1"
+    },
     "crc": {
       "version": "3.3.0"
     },

npm-shrinkwrap.json

@@ -2871,6 +2871,11 @@
       "from": "core-util-is@>=1.0.0 <1.1.0",
       "resolved": "https://registry.npmjs.org/core-util-is/-/core-util-is-1.0.2.tgz"
     },
+    "cors": {
+      "version": "2.7.1",
+      "from": "cors@>=2.7.1 <3.0.0",
+      "resolved": "https://registry.npmjs.org/cors/-/cors-2.7.1.tgz"
+    },
     "crc": {
       "version": "3.3.0",
       "from": "crc@3.3.0",

package.json

@@ -41,6 +41,7 @@
     "chokidar": "^1.1.0",
     "clang-format": "^1.0.32",
     "conventional-changelog": "^0.2.1",
+    "cors": "^2.7.1",
     "firefox-profile": "^0.3.4",
     "fs-extra": "^0.26.3",
     "glob": "^4.0.6",

tools/build/jsserve.js

@@ -1,5 +1,6 @@
 var onHeaders = require('on-headers');
 var proxy = require('proxy-middleware');
+var cors = require('cors');
 var url = require('url');
 
 module.exports = function(gulp, plugins, config) {
@@ -14,6 +15,7 @@ module.exports = function(gulp, plugins, config) {
         var middlewares =
             config.proxies.map(function(entry) { return makeProxy(entry.route, entry.url); });
         middlewares.push(connect.favicon());
+        middlewares.push(cors());
         // pub serve can't give the right content-type header for jsonp requests
         // so we must turn off Chromium strict MIME type checking
         // see https://github.com/angular/angular/issues/3030#issuecomment-123453168