Can I pass parameters to .js function when I create the new Web Workers object?

Question

When I create a web workers like the following...

 var w = new Worker("./Scripts/sample.js");

sample.js want to some parameters from the caller!!
Possible?

Answer 1

I haven't used web workers a whole bunch, but per this description I believe you could do it along these lines:

var worker = new Worker("sample.js");
worker.postMessage({ "args": [ ] });

Then, in sample.js, structure it along these lines:

self.addEventListener("message", function(e) {
  var args = e.data.args;
  // do whatever you need with the arguments
}, false);

This isn't quite the same as a traditional argument passing, as whatever goes in postMessage must be formattable as a JSON (eg no functions). But, there's a decent chance it can be made to do what you need it to do.

Answer 2

2018-July

location is available in WebWorkers ( according to MDN ), which opens up location.hash , location.search , and even location.pathname as ways of passing information. (Tested on Mac OSX in Chrome, Safari, FireFox)

Also, hash and query arguments worked in Chrome and FireFox for URL.createObjectURL(Blob([src])) , but not Safari.

(Apologies for the necroposting; search results are forever!)

Answer 3

Question

How can I pass parameters sample.js when using it as a web working like this var w = new Worker("./Scripts/sample.js"); ?

Answer

You can pass arguments in the query string and in sample.js get the arguments from location.search . You do not need to call postMessage to accomplish this.

Example Code

Calling code would be

var w = new Worker("./Scripts/sample.js?answer=42&question=ultimate");

This will call the worker. In sample.js location.search will equal ?answer=42&question=ultimate . We can use the following code to pull it out gracefully

var parameters = {}
location.search.slice(1).split("&").forEach( function(key_value) { var kv = key_value.split("="); parameters[kv[0]] = kv[1]; })

var question = parameters['question'];
var answer = parameters['answer'];

Live Example

You can see a live example here

Final Thoughts

If you have a large amount of data to send, don't use the query string.