:chick: initial commit

app/js/core/Loop.js

@@ -0,0 +1,52 @@
+class Loop {
+
+  constructor() {
+    this._idRAF = -1;
+    this._count = 0;
+
+    this._listeners = [];
+
+    this._binds = {};
+    this._binds.update = this._update.bind(this);
+  }
+
+  _update() {
+    let listener = null;
+    let i = this._count;
+    while (--i >= 0) {
+      listener = this._listeners[i];
+      if (listener) {
+        listener.apply(this, null);
+      }
+    }
+    this._idRAF = requestAnimationFrame(this._binds.update);
+  }
+
+  start() {
+    this._update();
+  }
+
+  stop() {
+    cancelAnimationFrame(this._idRAF);
+  }
+
+  add(listener) {
+    const idx = this._listeners.indexOf(listener);
+    if (idx >= 0) {
+      return;
+    }
+    this._listeners.push(listener);
+    this._count++;
+  }
+
+  remove(listener) {
+    const idx = this._listeners.indexOf(listener);
+    if (idx < 0) {
+      return;
+    }
+    this._listeners.splice(idx, 1);
+    this._count--;
+  }
+}
+
+module.exports = new Loop();