据我所知,web worker需要写在一个单独的JavaScript文件中,并像这样调用:

new Worker('longrunning.js')

我正在使用闭包编译器来合并和缩小我所有的JavaScript源代码,我不希望将我的worker放在单独的文件中进行分发。有什么办法可以做到吗?

new Worker(function() {
    //Long-running work here
});

既然一级函数对JavaScript如此重要,为什么标准的后台工作方式必须从web服务器加载整个其他JavaScript文件呢?


当前回答

我喜欢ifbamoq给出的答案,但由于堆栈溢出的积分政策,我无法评论。因此,我将给出一个示例,展示一些正在进行的密集工作——以及它如何不锁定主线程。

如果你像我一样双击html文件,把它们当成小程序,就不会遇到空原点的CORS问题。: -)

<!DOCTYPE html> <html> <head> <title>Worker example: One-core computation</title> </head> <body> <p>The highest prime number discovered so far is: <div id="result"></div></p> </body> <script> // let worker = new Worker('WebWorker.js'); // lets skip this to avoid null origin issues let WorkerFn = (event) => { let isPrime = false; for (let n = 2; n <= 1_000_000; n++) { isPrime = true; for(let i = 2; i <= Math.sqrt(n); i++) if (n % i == 0) isPrime = false; // If you can get thru all this shit and survive, ur prime! if (isPrime) postMessage(n); } } let worker = new Worker(window.URL.createObjectURL(new Blob(["(" + WorkerFn.toString() + ")()"], {type: "text/javascript"}))); worker.onmessage = (event) => { result.innerHTML = event.data; } </script> </html>

其他回答

这只是上面的一个补充-我在jsFiddle中有一个很好的模板用于测试web worker。而不是Blob,它使用jsFiddles ?js api:

function workerFN() {
  self.onmessage = function(e) {
    switch(e.data.name) {
      case "" : 
      break;
      default:
        console.error("Unknown message:", e.data.name);
    }
  }
}
// This is a trick to generate real worker script that is loaded from server
var url = "/echo/js/?js="+encodeURIComponent("("+workerFN.toString()+")()");
var worker = new Worker(url);
worker.addEventListener("message", function(e) {
  switch(e.data.name) {
    case "" : 
    break;
    default:
      console.error("Unknown message:", e.data.name);
  }
})

有普通的web worker模板和共享worker模板。

一个简单的承诺版本,Function#callAsWorker,它接受一个thisArg和参数(就像call一样),并返回一个承诺:

Function.prototype.callAsWorker = function (...args) { return new Promise( (resolve, reject) => { const code = `self.onmessage = e => self.postMessage((${this.toString()}).call(...e.data));`, blob = new Blob([code], { type: "text/javascript" }), worker = new Worker(window.URL.createObjectURL(blob)); worker.onmessage = e => (resolve(e.data), worker.terminate()); worker.onerror = e => (reject(e.message), worker.terminate()); worker.postMessage(args); }); } // Demo function add(...nums) { return nums.reduce( (a,b) => a+b ); } // Let the worker execute the above function, with the specified arguments add.callAsWorker(null, 1, 2, 3).then(function (result) { console.log('result: ', result); });

https://developer.mozilla.org/es/docs/Web/Guide/Performance/Using_web_workers

    // Syntax: asyncEval(code[, listener])

var asyncEval = (function () {

  var aListeners = [], oParser = new Worker("data:text/javascript;charset=US-ASCII,onmessage%20%3D%20function%20%28oEvent%29%20%7B%0A%09postMessage%28%7B%0A%09%09%22id%22%3A%20oEvent.data.id%2C%0A%09%09%22evaluated%22%3A%20eval%28oEvent.data.code%29%0A%09%7D%29%3B%0A%7D");

  oParser.onmessage = function (oEvent) {
    if (aListeners[oEvent.data.id]) { aListeners[oEvent.data.id](oEvent.data.evaluated); }
    delete aListeners[oEvent.data.id];
  };


  return function (sCode, fListener) {
    aListeners.push(fListener || null);
    oParser.postMessage({
      "id": aListeners.length - 1,
      "code": sCode
    });
  };

})();

将Adria的响应放在一个可复制粘贴的函数中,该函数适用于当前的Chrome和FF,但不适用于IE10 (worker from blob会导致安全错误)。

var newWorker = function (funcObj) {
    // Build a worker from an anonymous function body
    var blobURL = URL.createObjectURL(new Blob(
        ['(', funcObj.toString(), ')()'],
        {type: 'application/javascript'}
     ));

    var worker = new Worker(blobURL);

    // Won't be needing this anymore
    URL.revokeObjectURL(blobURL);

    return worker;
}

下面是一个工作示例http://jsfiddle.net/ubershmekel/YYzvr/

使用我的小插件https://github.com/zevero/worker-create

var worker_url = Worker.createURL(function(e){
  self.postMessage('Example post from Worker'); //your code here
});
var worker = new Worker(worker_url);