watcher should continue aggregating changes even when paused

add method to get aggregated info

Author: sokra

README.md

@@ -98,11 +98,20 @@ wp.on("aggregated", function(changes, removals) {
 wp.pause();
 // stops emitting events, but keeps watchers open
 // next "watch" call can reuse the watchers
+// The watcher will keep aggregating events
+// which can be received with getAggregated()
 
 // Watchpack.prototype.close()
 wp.close();
 // stops emitting events and closes all watchers
 
+// Watchpack.prototype.getAggregated(): { changes: Set<string>, removals: Set<string> }
+const { changes, removals } = wp.getAggregated();
+// returns the current aggregated info and removes that from the watcher
+// The next aggregated event won't include that info and will only emitted
+// when futher changes happen
+// Can also be used when paused.
+
 // Watchpack.prototype.getTimeInfoEntries()
 var fileTimes = wp.getTimeInfoEntries();
 // returns a Map with all known time info objects for files and directories

lib/watchpack.js

@@ -302,24 +302,38 @@ class Watchpack extends EventEmitter {
 		return map;
 	}
 
+	getAggregated() {
+		if (this.aggregateTimer) {
+			clearTimeout(this.aggregateTimer);
+			this.aggregateTimer = undefined;
+		}
+		const changes = this.aggregatedChanges;
+		const removals = this.aggregatedRemovals;
+		this.aggregatedChanges = new Set();
+		this.aggregatedRemovals = new Set();
+		return { changes, removals };
+	}
+
 	_onChange(item, mtime, file, type) {
 		file = file || item;
-		if (this.paused) return;
-		this.emit("change", file, mtime, type);
-		if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
+		if (!this.paused) {
+			this.emit("change", file, mtime, type);
+			if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
+			this.aggregateTimer = setTimeout(this._onTimeout, this.aggregateTimeout);
+		}
 		this.aggregatedRemovals.delete(item);
 		this.aggregatedChanges.add(item);
-		this.aggregateTimer = setTimeout(this._onTimeout, this.aggregateTimeout);
 	}
 
 	_onRemove(item, file, type) {
 		file = file || item;
-		if (this.paused) return;
-		this.emit("remove", file, type);
-		if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
+		if (!this.paused) {
+			this.emit("remove", file, type);
+			if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
+			this.aggregateTimer = setTimeout(this._onTimeout, this.aggregateTimeout);
+		}
 		this.aggregatedChanges.delete(item);
 		this.aggregatedRemovals.add(item);
-		this.aggregateTimer = setTimeout(this._onTimeout, this.aggregateTimeout);
 	}
 
 	_onTimeout() {

test/Watchpack.js

@@ -35,6 +35,37 @@ describe("Watchpack", function() {
 		});
 	});
 
+	it("should aggregate changes while paused", function(done) {
+		var w = new Watchpack({
+			aggregateTimeout: 1000
+		});
+		testHelper.file("a");
+		testHelper.file("b");
+		w.watch([path.join(fixtures, "a"), path.join(fixtures, "b")], []);
+		testHelper.tick(function() {
+			w.pause();
+			w.on("change", function(file) {
+				throw new Error("should not be emitted");
+			});
+			w.on("aggregated", function(changes) {
+				throw new Error("should not be emitted");
+			});
+			testHelper.tick(function() {
+				testHelper.file("a");
+				testHelper.remove("b");
+				testHelper.file("b");
+				testHelper.remove("a");
+				testHelper.tick(function() {
+					const { changes, removals } = w.getAggregated();
+					Array.from(changes).should.be.eql([path.join(fixtures, "b")]);
+					Array.from(removals).should.be.eql([path.join(fixtures, "a")]);
+					w.close();
+					done();
+				});
+			});
+		});
+	});
+
 	it("should not watch a single ignored file (glob)", function(done) {
 		var w = new Watchpack({
 			aggregateTimeout: 300,