// 判断浏览器是否支持 Worker
typeof Worker !== "undefined";

// 从脚本中创建 Worker
new Worker("workers.js");

// 使用字符串方式创建 Worker
new Worker("data:text/javascript;charset=US-ASCII,...");

import Worker from "worker-loader!./file.worker.js";

const worker = new Worker();

// 转化为下述代码
const blob = new Blob([codeFromFileWorker], { type: "application/javascript" });
const worker = new Worker(URL.createObjectURL(blob));

const code = `
  importScripts('https://xxx.com/xxx.js');
  self.onmessage = e => {};
`;

const blob = new Blob([code], { type: "application/javascript" });
const worker = new Worker(URL.createObjectURL(blob));

function XHRWorker(url, ready, scope) {
  var oReq = new XMLHttpRequest();
  oReq.addEventListener(
    "load",
    function() {
      var worker = new Worker(
        window.URL.createObjectURL(new Blob([this.responseText]))
      );
      if (ready) {
        ready.call(scope, worker);
      }
    },
    oReq
  );
  oReq.open("get", url, true);
  oReq.send();
}

function WorkerStart() {
  XHRWorker(
    "http://static.xxx.com/js/worker.js",
    function(worker) {
      worker.postMessage("hello world");
      worker.onmessage = function(e) {
        console.log(e.data);
      };
    },
    this
  );
}

WorkerStart();

// worker.js
// 向主线程发送消息
postMessage("event from worker");
// 接收来自主线程的消息
onmessage = function(event) {};

// UI
worker.onmessage = function(event) {};
worker.postMessage("event from ui");

// 关闭当前 worker
worker.terminate();

// main
var worker = new Worker("./worker.js");

worker.onmessage = function getMessageFromWorker(e) {
  // 被改造后的数据，与原数据对比，表明数据是被克隆了一份
  console.log("e.data", "   -- ", e.data);
  // [2, 3, 4]

  // msg 依旧是原本的 msg，没有任何改变
  console.log("msg", "   -- ", msg);
  // [1, 2, 3]
};

var msg = [1, 2, 3];

worker.postMessage(msg);

// worker
onmessage = function(e) {
  var newData = increaseData(e.data);
  postMessage(newData);
};

function increaseData(data) {
  for (let i = 0; i < data.length; i++) {
    data[i] += 1;
  }

  return data;
}

var ab = new ArrayBuffer(1);
worker.postMessage(ab, [ab]);

// main.js
var worker = new Worker("./sharedArrayBufferWorker.js");

worker.onmessage = function(e) {
  // 传回到主线程已经被计算过的数据
  console.log("e.data", "   -- ", e.data);
  // SharedArrayBuffer(3) {}

  // 和传统的 postMessage 方式对比，发现主线程的原始数据发生了改变
  console.log("int8Array-outer", "   -- ", int8Array);
  // Int8Array(3) [2, 3, 4]
};

var sharedArrayBuffer = new SharedArrayBuffer(3);
var int8Array = new Int8Array(sharedArrayBuffer);

int8Array[0] = 1;
int8Array[1] = 2;
int8Array[2] = 3;

worker.postMessage(sharedArrayBuffer);

// worker.js
onmessage = function(e) {
  var arrayData = increaseData(e.data);
  postMessage(arrayData);
};

function increaseData(arrayData) {
  var int8Array = new Int8Array(arrayData);
  for (let i = 0; i < int8Array.length; i++) {
    int8Array[i] += 1;
  }

  return arrayData;
}