1 files changed, 40 insertions, 0 deletions
diff --git a/webclients/novnc/core/util/eventtarget.js b/webclients/novnc/core/util/eventtarget.js
new file mode 100644
index 0000000..61bc7a1
--- /dev/null
+++ b/webclients/novnc/core/util/eventtarget.js
@@ -0,0 +1,40 @@
+/*
+ * noVNC: HTML5 VNC client
+ * Copyright 2017 Pierre Ossman for Cendio AB
+ * Licensed under MPL 2.0 (see LICENSE.txt)
+ *
+ * See README.md for usage and integration instructions.
+ */
+
+var EventTargetMixin = {
+    _listeners: null,
+
+   addEventListener: function(type, callback) {
+      if (!this._listeners) {
+         this._listeners = new Map();
+      }
+      if (!this._listeners.has(type)) {
+         this._listeners.set(type, new Set());
+      }
+      this._listeners.get(type).add(callback);
+   },
+
+   removeEventListener: function(type, callback) {
+      if (!this._listeners || !this._listeners.has(type)) {
+         return;
+      }
+      this._listeners.get(type).delete(callback);
+   },
+
+   dispatchEvent: function(event) {
+      if (!this._listeners || !this._listeners.has(event.type)) {
+         return true;
+      }
+      this._listeners.get(event.type).forEach(function (callback) {
+         callback.call(this, event);
+      }, this);
+      return !event.defaultPrevented;
+   },
+};
+
+export default EventTargetMixin;