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

控制台:

var worker=new Worker(window.URL.createObjectURL(new Blob([function(){
  //Long-running work here
  postMessage('done');
}.toString().split('\n').slice(1,-1).join('\n')],{type:'text/javascript'})));

worker.addEventListener('message',function(event){
  console.log(event.data);
});

其他回答

看一下vkThread插件。使用htis插件,你可以在主代码中获取任何函数,并在线程(web worker)中执行它。所以,你不需要创建一个特殊的“web-worker文件”。

http://www.eslinstructor.net/vkthread/

——瓦迪姆

一个更好的阅读方式为内联工人..

    var worker_fn = function(e) 
    {
        self.postMessage('msg from worker');            
    };

    var blob = new Blob(["onmessage ="+worker_fn.toString()], { type: "text/javascript" });

    var worker = new Worker(window.URL.createObjectURL(blob));
    worker.onmessage = function(e) 
    {
       alert(e.data);
    };
    worker.postMessage("start"); 

是的,这是可能的,我做到了使用Blob文件和传递回调

我将向您展示我编写的一个类是做什么的,以及它如何在后台管理回调的执行。

首先,你要实例化GenericWebWorker,使用你想要传递给回调的任何数据,这些数据将在WebWorker中执行,包括你想要使用的函数,在这种情况下,一个数字,一个日期和一个叫做blocker的函数

var worker = new GenericWebWorker(100, new Date(), blocker)

这个阻塞器函数将在n毫秒内执行一个无限while

function blocker (ms) {
    var now = new Date().getTime();
    while(true) {
        if (new Date().getTime() > now +ms)
            return;
    }   
}

然后像这样用

worker.exec((num, date, fnBlocker) => {
    /*Everithing here does not block the main thread
      and this callback has access to the number, date and the blocker */
    fnBlocker(10000) //All of this run in backgrownd
    return num*10

}).then(d => console.log(d)) //Print 1000

现在,是时候看看下面例子中的神奇之处了

/*https://github.com/fercarvo/GenericWebWorker*/ class GenericWebWorker { constructor(...ags) { this.args = ags.map(a => (typeof a == 'function') ? {type:'fn', fn:a.toString()} : a) } async exec(cb) { var wk_string = this.worker.toString(); wk_string = wk_string.substring(wk_string.indexOf('{') + 1, wk_string.lastIndexOf('}')); var wk_link = window.URL.createObjectURL( new Blob([ wk_string ]) ); var wk = new Worker(wk_link); wk.postMessage({ callback: cb.toString(), args: this.args }); var resultado = await new Promise((next, error) => { wk.onmessage = e => (e.data && e.data.error) ? error(e.data.error) : next(e.data); wk.onerror = e => error(e.message); }) wk.terminate(); window.URL.revokeObjectURL(wk_link); return resultado } async parallel(arr, cb) { var res = [...arr].map(it => new GenericWebWorker(it, ...this.args).exec(cb)) var all = await Promise.all(res) return all } worker() { onmessage = async function (e) { try { var cb = new Function(`return ${e.data.callback}`)(); var args = e.data.args.map(p => (p.type == 'fn') ? new Function(`return ${p.fn}`)() : p); try { var result = await cb.apply(this, args); //If it is a promise or async function return postMessage(result) } catch (e) { throw new Error(`CallbackError: ${e}`) } } catch (e) { postMessage({error: e.message}) } } } } function blocker (ms) { var now = new Date().getTime(); while(true) { if (new Date().getTime() > now +ms) return; } } setInterval(()=> console.log("Not blocked " + Math.random()), 1000) console.log("\n\nstarting blocking code in Worker\n\n") var worker = new GenericWebWorker(100, new Date(), blocker) worker.exec((num, date, fnBlocker) => { fnBlocker(7000) //All of this run in backgrownd return num*10 }) .then(d => console.log(`\n\nEnd of blocking code: result ${d}\n\n`)) //Print 1000

我认为更好的方法是使用Blob对象,下面你可以看到一个简单的例子。

// create a Blob object with a worker code
var blob = new Blob(["onmessage = function(e) { postMessage('msg from worker'); }"]);

// Obtain a blob URL reference to our worker 'file'.
var blobURL = window.URL.createObjectURL(blob);

// create a Worker
var worker = new Worker(blobURL);
worker.onmessage = function(e) {
  console.log(e.data);
};
worker.postMessage("Send some Data"); 

对于Node.js实现,可以使用以下对Trincot答案的改编。再次注意,Function.prototype.callAsWorker()接受一个thisArg和参数,就像Function.prototype.call()一样,并返回一个承诺。

const { Worker } = require ( 'worker_threads' );

Function.prototype.callAsWorker = function ( ...args ) {
    return new Promise( ( resolve, reject ) => {

        const code = `
            const { parentPort, workerData } = require ( 'worker_threads' );
            parentPort.postMessage( ( ${this.toString()} ).call( ...workerData ) )
        `;
        const worker = new Worker( code, { eval: true, workerData: args } );
            
        worker.on('message', ( msg ) => { resolve( msg ), worker.terminate() } );
        worker.on('error', ( err ) => { reject( err ), worker.terminate() } );
        worker.on('exit', ( code ) => {
            if ( code !== 0 ) {
                reject( new Error( `Worker stopped with exit code ${code}.` ) );
            }
        });

    });
}

// Demo
function add( ...nums ) {
    return nums.reduce( ( a, b ) => a + b );
}

// Let the worker execute the above function, with the specified arguments
let result = await add.callAsWorker( null, 1, 2, 3 );
console.log( 'result: ', result );