Merge pull request #8253 from renatoagds/compiler-watch-mode

Adding watchMode flag in compiler

lib/Compiler.js

@@ -184,12 +184,16 @@ class Compiler extends Tapable {
 
 		/** @type {boolean} */
 		this.running = false;
+
+		/** @type {boolean} */
+		this.watchMode = false;
 	}
 
 	watch(watchOptions, handler) {
 		if (this.running) return handler(new ConcurrentCompilationError());
 
 		this.running = true;
+		this.watchMode = true;
 		this.fileTimestamps = new Map();
 		this.contextTimestamps = new Map();
 		return new Watching(this, watchOptions, handler);

lib/Watching.js

@@ -170,6 +170,7 @@ class Watching {
 		const finalCallback = () => {
 			this.compiler.hooks.watchClose.call();
 			this.compiler.running = false;
+			this.compiler.watchMode = false;
 			if (callback !== undefined) callback();
 		};
 

test/Compiler.test.js

@@ -448,6 +448,28 @@ describe("Compiler", () => {
 			});
 		});
 	});
+	it("should flag watchMode as true in watch", function(done) {
+		const compiler = webpack({
+			context: __dirname,
+			mode: "production",
+			entry: "./c",
+			output: {
+				path: "/",
+				filename: "bundle.js"
+			}
+		});
+
+		compiler.outputFileSystem = new MemoryFs();
+
+		const watch = compiler.watch({}, err => {
+			if (err) return done(err);
+			expect(compiler.watchMode).toBeTruthy();
+			watch.close(() => {
+				expect(compiler.watchMode).toBeFalsy();
+				done();
+			});
+		});
+	});
 	it("should use cache on second run call", function(done) {
 		const compiler = webpack({
 			context: __dirname,