javascript web workers - how do I pass arguments?

Question

Found the answer some some of my problems, html5 web workers!!!

How do I pass an argument to a web worker though using this basic example?

contents of worker.js:

function doSomething() {
    postMessage( ' done');
}
setTimeout ( "doSomething()", 3000 );

js code:

 var worker = new Worker('worker.js');
  worker.onmessage = function (event) {
    alert(event.data);
  };

Use setTimeout like so: `setTimeout( doSomething, 3000 );` It's better because there is no extra evaluation going on... — Šime Vidas, Oct 25 '10 at 22:10

Šime Vidas · Accepted Answer · 2010-10-25T22:25:22.860

54

As you can see you have the same mechanism for both worker-to-main and main-to-worker messages.

the postMessage method for sending messages
the onmessage member for defining the handler that receives the messages

In the main script:

worker.postMessage(data);

In the worker script:

self.addEventListener("message", function(e) {
    // the passed-in data is available via e.data
}, false);

... or just...

onmessage = function(e) {
    // the passed-in data is available via e.data
};

It may be that data has to be a string... (Firefox 3.5+ supports passing in JSON-compatible objects)

edited Oct 25 '10 at 22:25

answered Oct 25 '10 at 22:09

Šime Vidas

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1

what is self there? in self.addEventListener? – Andrei Cristian Prodan Feb 25 '14 at 16:22
2

@AndreiCristianProdan The worker's global scope, like `window` on a web page. Docs: http://msdn.microsoft.com/en-us/library/windows/apps/hh453270.aspx – Šime Vidas Feb 28 '14 at 03:39
Probably you should look here: https://stackoverflow.com/a/55680502/3559690 as they have described a pretty nice way – hsc Jan 12 '20 at 07:37

score 0 · Answer 2 · answered Mar 15 '17 at 19:56

 var worker = new Worker(window.App.baseUrl + '/Scripts/signature/GetCurrenProductWorker.js');
                    worker.postMessage(window.App.baseUrl)


    var _base_url = ''
        var xhr = new XMLHttpRequest();
        onmessage = function (e) {
            _base_url = e.data
            xhr.open("GET", _base_url + "/api/product/Get");
            xhr.onload = function () {
                postMessage(xhr.responseText);
            };
            xhr.send();

        };

this work for me

javascript web workers - how do I pass arguments?

2 Answers2

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