Allow function in watchOptions.ignored

README.md

@@ -49,6 +49,7 @@ var wp = new Watchpack({
 	// ignored: "string" - a glob pattern for files or folders that should not be watched
 	// ignored: ["string", "string"] - multiple glob patterns that should be ignored
 	// ignored: /regexp/ - a regular expression for files or folders that should not be watched
+	// ignored: (entry) => boolean - an arbirary function which must return truthy to ignore an entry
 	// All subdirectories are ignored too
 });
 

lib/watchpack.js

@@ -31,13 +31,15 @@ const stringToRegexp = ignored => {
 	return matchingStart;
 };
 
-const ignoredToRegexp = ignored => {
+const ignoredToRegexpLike = ignored => {
 	if (Array.isArray(ignored)) {
 		return new RegExp(ignored.map(i => stringToRegexp(i)).join("|"));
 	} else if (typeof ignored === "string") {
 		return new RegExp(stringToRegexp(ignored));
 	} else if (ignored instanceof RegExp) {
 		return ignored;
+	} else if (ignored instanceof Function) {
+		return { test: ignored };
 	} else if (ignored) {
 		throw new Error(`Invalid option for 'ignored': ${ignored}`);
 	} else {
@@ -48,7 +50,7 @@ const ignoredToRegexp = ignored => {
 const normalizeOptions = options => {
 	return {
 		followSymlinks: !!options.followSymlinks,
-		ignored: ignoredToRegexp(options.ignored),
+		ignored: ignoredToRegexpLike(options.ignored),
 		poll: options.poll
 	};
 };

test/Watchpack.js

@@ -118,6 +118,32 @@ describe("Watchpack", function() {
 		});
 	});
 
+	it("should not watch a single ignored file (function)", function(done) {
+		var w = new Watchpack({
+			aggregateTimeout: 300,
+			ignored: (entry) => entry.includes("a")
+		});
+		var changeEvents = 0;
+		var aggregatedEvents = 0;
+		w.on("change", () => {
+			changeEvents++;
+		});
+		w.on("aggregated", () => {
+			aggregatedEvents++;
+		});
+		w.watch([path.join(fixtures, "a")], []);
+		testHelper.tick(() => {
+			testHelper.file("a");
+			testHelper.tick(1000, () => {
+				changeEvents.should.be.eql(0);
+				aggregatedEvents.should.be.eql(0);
+				testHelper.getNumberOfWatchers().should.be.eql(0);
+				w.close();
+				done();
+			});
+		});
+	});
+
 	it("should watch multiple files", function(done) {
 		var w = new Watchpack({
 			aggregateTimeout: 1000