fix: plugin usage

Author: alexander-akait

lib/Server.js

@@ -15,6 +15,8 @@ if (!process.env.WEBPACK_SERVE) {
   process.env.WEBPACK_SERVE = true;
 }
 
+const pluginName = "webpack-dev-server";
+
 class Server {
   constructor(options = {}, compiler) {
     // TODO: remove this after plugin support is published
@@ -41,11 +43,6 @@ class Server {
     }
   }
 
-  apply(compiler) {
-    this.compiler = compiler;
-    this.start();
-  }
-
   static get DEFAULT_STATS() {
     return {
       all: false,
@@ -134,6 +131,20 @@ class Server {
     return path.resolve(dir, "node_modules/.cache/webpack-dev-server");
   }
 
+  apply(compiler) {
+    this.compiler = compiler;
+
+    let started = false;
+
+    compiler.hooks.watchRun.tapPromise(pluginName, async () => {
+      if (!started) {
+        await this.start();
+
+        started = true;
+      }
+    });
+  }
+
   addAdditionalEntries(compiler) {
     const additionalEntries = [];
 
@@ -403,7 +414,7 @@ class Server {
     const { options } = this;
 
     if (!this.logger) {
-      this.logger = this.compiler.getInfrastructureLogger("webpack-dev-server");
+      this.logger = this.compiler.getInfrastructureLogger(pluginName);
     }
 
     const compilerOptions = this.getCompilerOptions();
@@ -696,7 +707,7 @@ class Server {
     if (typeof options.ipc === "boolean") {
       const isWindows = process.platform === "win32";
       const pipePrefix = isWindows ? "\\\\.\\pipe\\" : os.tmpdir();
-      const pipeName = "webpack-dev-server.sock";
+      const pipeName = `${pluginName}.sock`;
 
       options.ipc = path.join(pipePrefix, pipeName);
     }
@@ -1158,12 +1169,12 @@ class Server {
   }
 
   setupHooks() {
-    this.compiler.hooks.invalid.tap("webpack-dev-server", () => {
+    this.compiler.hooks.invalid.tap(pluginName, () => {
       if (this.webSocketServer) {
         this.sendMessage(this.webSocketServer.clients, "invalid");
       }
     });
-    this.compiler.hooks.done.tap("webpack-dev-server", (stats) => {
+    this.compiler.hooks.done.tap(pluginName, (stats) => {
       if (this.webSocketServer) {
         this.sendStats(this.webSocketServer.clients, this.getStats(stats));
       }
@@ -2146,7 +2157,7 @@ class Server {
     }
   }
 
-  startCallback(callback) {
+  startCallback(callback = () => {}) {
     this.start().then(() => callback(null), callback);
   }
 
@@ -2218,7 +2229,7 @@ class Server {
       "DEP_WEBPACK_DEV_SERVER_LISTEN"
     )();
 
-    this.logger = this.compiler.getInfrastructureLogger("webpack-dev-server");
+    this.logger = this.compiler.getInfrastructureLogger(pluginName);
 
     if (typeof port === "function") {
       fn = port;