Fix: Only emit error events when there is a listener (fixes #35) (#36)

Author: phated

index.js

@@ -12,6 +12,18 @@ var defaultOpts = {
   queue: true,
 };
 
+function listenerCount(ee, evtName) {
+  if (typeof ee.listenerCount === 'function') {
+    return ee.listenerCount(evtName);
+  }
+
+  return ee.listeners(evtName).length;
+}
+
+function hasErrorListener(ee) {
+  return listenerCount(ee, 'error') !== 0;
+}
+
 function watch(glob, options, cb) {
   if (typeof options === 'function') {
     cb = options;
@@ -32,7 +44,7 @@ function watch(glob, options, cb) {
   function runComplete(err) {
     running = false;
 
-    if (err) {
+    if (err && hasErrorListener(watcher)) {
       watcher.emit('error', err);
     }
 

test/index.js

@@ -159,7 +159,7 @@ describe('glob-watcher', function() {
     });
   });
 
-  it('emits an error if one occurs in the callback', function(done) {
+  it('emits an error if one occurs in the callback and handler attached', function(done) {
     var expectedError = new Error('boom');
 
     watcher = watch(outGlob, function(cb) {
@@ -175,6 +175,18 @@ describe('glob-watcher', function() {
     watcher.on('ready', changeFile);
   });
 
+  it('does not emit an error (and crash) when no handlers attached', function(done) {
+    var expectedError = new Error('boom');
+
+    watcher = watch(outGlob, function(cb) {
+      cb(expectedError);
+      setTimeout(done, timeout * 3);
+    });
+
+    // We default `ignoreInitial` to true, so always wait for `on('ready')`
+    watcher.on('ready', changeFile);
+  });
+
   it('allows the user to disable queueing', function(done) {
     var runs = 0;