From fc0df304c0d96d19f1b2b137057721b5e175fe2a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Lorber?= <slorber@users.noreply.github.com>
Date: Thu, 16 Dec 2021 12:02:29 +0100
Subject: [PATCH] feat(core): allow plugins to customize/override Webpack
 devServer config (#6107)

---
 packages/docusaurus/src/commands/start.ts | 29 +++++++++++++----------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/packages/docusaurus/src/commands/start.ts b/packages/docusaurus/src/commands/start.ts
index d6bad0d75f..ce6f003ab9 100644
--- a/packages/docusaurus/src/commands/start.ts
+++ b/packages/docusaurus/src/commands/start.ts
@@ -166,8 +166,20 @@ export default async function start(
     }
   });
 
+  const compiler = webpack(config);
+  if (process.env.E2E_TEST) {
+    compiler.hooks.done.tap('done', (stats) => {
+      if (stats.hasErrors()) {
+        console.log('E2E_TEST: Project has compiler errors.');
+        process.exit(1);
+      }
+      console.log('E2E_TEST: Project can compile.');
+      process.exit(0);
+    });
+  }
+
   // https://webpack.js.org/configuration/dev-server
-  const devServerConfig: WebpackDevServer.Configuration = {
+  const defaultDevServerConfig: WebpackDevServer.Configuration = {
     hot: cliOptions.hotOnly ? 'only' : true,
     liveReload: false,
     client: {
@@ -222,17 +234,10 @@ export default async function start(
     },
   };
 
-  const compiler = webpack(config);
-  if (process.env.E2E_TEST) {
-    compiler.hooks.done.tap('done', (stats) => {
-      if (stats.hasErrors()) {
-        console.log('E2E_TEST: Project has compiler errors.');
-        process.exit(1);
-      }
-      console.log('E2E_TEST: Project can compile.');
-      process.exit(0);
-    });
-  }
+  // Allow plugin authors to customize/override devServer config
+  const devServerConfig: WebpackDevServer.Configuration = merge(
+    [defaultDevServerConfig, config.devServer].filter(Boolean),
+  );
 
   const devServer = new WebpackDevServer(devServerConfig, compiler);
   devServer.startCallback(() => {