feat(@angular-devkit/build-webpack): expose DevServerResult in BuildEvent

Author: Alan Agius

packages/angular_devkit/build_webpack/src/webpack-dev-server/index.ts

@@ -12,20 +12,27 @@ import {
   BuilderConfiguration,
   BuilderContext,
 } from '@angular-devkit/architect';
-import { Path, getSystemPath, normalize, resolve } from '@angular-devkit/core';
+import { getSystemPath, normalize, resolve } from '@angular-devkit/core';
+import * as net from 'net';
 import { Observable, from } from 'rxjs';
 import { concatMap } from 'rxjs/operators';
 import * as webpack from 'webpack';
 import * as WebpackDevServer from 'webpack-dev-server';
 import { LoggingCallback, defaultLoggingCb } from '../webpack';
 import { WebpackDevServerBuilderSchema } from './schema';
 
+export interface DevServerResult {
+  port: number;
+  family: string;
+  address: string;
+}
 
 export class WebpackDevServerBuilder implements Builder<WebpackDevServerBuilderSchema> {
 
   constructor(public context: BuilderContext) { }
 
-  run(builderConfig: BuilderConfiguration<WebpackDevServerBuilderSchema>): Observable<BuildEvent> {
+  run(builderConfig: BuilderConfiguration<WebpackDevServerBuilderSchema>)
+    : Observable<BuildEvent<DevServerResult>> {
     const configPath = resolve(this.context.workspace.root,
       normalize(builderConfig.options.webpackConfig));
 
@@ -42,11 +49,13 @@ export class WebpackDevServerBuilder implements Builder<WebpackDevServerBuilderS
     webpackConfig: webpack.Configuration,
     devServerCfg?: WebpackDevServer.Configuration,
     loggingCb: LoggingCallback = defaultLoggingCb,
-  ): Observable<BuildEvent> {
+  ): Observable<BuildEvent<DevServerResult>> {
     return new Observable(obs => {
       const devServerConfig = devServerCfg || webpackConfig.devServer || {};
       devServerConfig.host = devServerConfig.host || 'localhost';
-      devServerConfig.port = devServerConfig.port || 8080;
+      if (devServerConfig.port == undefined) {
+        devServerConfig.port = 8080;
+      }
 
       if (devServerConfig.stats) {
         webpackConfig.stats = devServerConfig.stats as webpack.Stats.ToStringOptionsObject;
@@ -56,20 +65,26 @@ export class WebpackDevServerBuilder implements Builder<WebpackDevServerBuilderS
 
       const webpackCompiler = webpack(webpackConfig);
       const server = new WebpackDevServer(webpackCompiler, devServerConfig);
+      let result: undefined | DevServerResult;
 
       webpackCompiler.hooks.done.tap('build-webpack', (stats) => {
         // Log stats.
         loggingCb(stats, webpackConfig, this.context.logger);
 
-        obs.next({ success: !stats.hasErrors() });
+        obs.next({ success: !stats.hasErrors(), result });
       });
 
       server.listen(
         devServerConfig.port,
         devServerConfig.host,
-        (err) => {
+        function (err) {
           if (err) {
             obs.error(err);
+          } else {
+            // this is ignored because of ts errors
+            // that this is overshadowed by it's outer contain
+            // @ts-ignore;
+            result = (this as net.Server).address();
           }
         },
       );