# TaskWorker(任务调度器)

TaskWorker makes [WebWorkers][webworker] enjoyable. TaskWorker is a **tiny library (1.1kB)**, that removes the mental barrier of thinking about `postMessage` and hides the fact that you are working with workers.

At a more abstract level it is an RPC implementation for `postMessage` and [ES6 Proxies][es6 proxy].

```
$ npm install --save @kuiu/task-worker
```

## Introduction

On mobile phones, and especially on low-end mobile phones, it is important to keep the main thread as idle as possible so it can respond to user interactions quickly and provide a jank-free experience. **The UI thread ought to be for UI work only**. WebWorkers are a web API that allow you to run code in a separate thread. To communicate with another thread, WebWorkers offer the `postMessage` API. You can send JavaScript objects as messages using `myWorker.postMessage(someObject)`, triggering a `message` event inside the worker.

TaskWorker turns this messaged-based API into a something more developer-friendly by providing an RPC implementation: Values from one thread can be used within the other thread (and vice versa) just like local values.




**main.js**

```javascript
import * as TaskWorker from "@kuiu/task-worker";
async function init() {
  // WebWorkers use `postMessage` and therefore work with TaskWorker.
  const obj = TaskWorker.createTaskPorxy([new Worker("worker.js"), new Worker("worker.js")], [], null, true);
  alert(`Counter: ${await obj.counter}`);
  await obj.initial();
  alert(`Counter: ${await obj.counter}`);
}
init();
```

**worker.js**

```javascript
const obj = {
  counter: 0,
  inc() {
    this.counter++;
  },
};

const Worker = new TaskWorker.TaskWorker(self)
Worker.expose('default', obj);
```



**main.js**

```javascript
function callback(value) {
  alert(`Result: ${value}`);
}
async function init() {
  const remoteFunction = TaskWorker.createTaskPorxy([new Worker("worker.js")], [], null, true);
  await remoteFunction(TaskWorker.proxy(callback));
}
init();
```

**worker.js**

```javascript
async function remoteFunction(cb) {
  await cb("A string from a worker");
}
const Worker = new TaskWorker.TaskWorker(self)
Worker.expose('default', remoteFunction);
```