fix(@angular/cli): prefix historyApiFallback.index with deployUrl (#6279)

Author: smoke

packages/@angular/cli/tasks/serve.ts

@@ -162,6 +162,13 @@ export default Task.extend({
 
     webpackDevServerConfiguration.hot = serveTaskOptions.hmr;
 
+    // set publicPath property to be sent on webpack server config
+    if (serveTaskOptions.deployUrl) {
+      webpackDevServerConfiguration.publicPath = serveTaskOptions.deployUrl;
+      (webpackDevServerConfiguration.historyApiFallback as any).index =
+        serveTaskOptions.deployUrl + `/${appConfig.index}`;
+    }
+
     if (serveTaskOptions.target === 'production') {
       ui.writeLine(chalk.red(stripIndents`
         ****************************************************************************************

tests/e2e/tests/misc/deploy-url.ts

@@ -0,0 +1,22 @@
+import { killAllProcesses } from '../../utils/process';
+import { request } from '../../utils/http';
+import { ngServe } from '../../utils/project';
+
+export default function () {
+  return Promise.resolve()
+    // check when setup through command line arguments
+    .then(() => ngServe('--deploy-url', '/deployurl/', '--base-href', '/deployurl/'))
+    .then(() => request('http://localhost:4200'))
+    .then(body => {
+      if (!body.match(/<app-root><\/app-root>/)) {
+        throw new Error('Response does not match expected value.');
+      }
+    })
+    .then(() => request('http://localhost:4200/deployurl/'))
+    .then(body => {
+      if (!body.match(/<app-root><\/app-root>/)) {
+        throw new Error('Response does not match expected value.');
+      }
+    })
+    .then(() => killAllProcesses(), (err) => { killAllProcesses(); throw err; });
+}