perf(demo): improve main cpu loop performance

1 files changed, 39 insertions, 0 deletions

diff --git a/demo/src/task-scheduler.ts b/demo/src/task-scheduler.ts
new file mode 100644
index 0000000..5364d92
--- /dev/null
+++ b/demo/src/task-scheduler.ts
@@ -0,0 +1,39 @@
+// Faster setTimeout(fn, 0) implementation using postMessage API
+// Based on https://dbaron.org/log/20100309-faster-timeouts
+export type IMicroTaskCallback = () => void;
+
+export class MicroTaskScheduler {
+  readonly messageName = 'zero-timeout-message';
+
+  private executionQueue: Array<IMicroTaskCallback> = [];
+  private stopped = true;
+
+  start() {
+    if (this.stopped) {
+      this.stopped = false;
+      window.addEventListener('message', this.handleMessage, true);
+    }
+  }
+
+  stop() {
+    this.stopped = true;
+    window.removeEventListener('message', this.handleMessage, true);
+  }
+
+  postTask(fn: IMicroTaskCallback) {
+    if (!this.stopped) {
+      this.executionQueue.push(fn);
+      window.postMessage(this.messageName, '*');
+    }
+  }
+
+  private handleMessage = (event: MessageEvent) => {
+    if (event.data === this.messageName) {
+      event.stopPropagation();
+      const executeJob = this.executionQueue.shift();
+      if (executeJob !== undefined) {
+        executeJob();
+      }
+    }
+  };
+}