Web Workers - Transferable Objects for JSON

HTML 5 Web workers are very slow when using worker.postMessage on a large JSON object. I'm trying to figure out how to transfer a JSON Object to a web worker - using the 'Transferable Objects' types in Chrome, in order to increase the speed of this.

Here is what I'm referring to and appears it should speed this up quite a bit: http://updates.html5rocks.com/2011/12/Transferable-Objects-Lightning-Fast

I'm having trouble finding a good example of this (and I don't believe I want to use an ArrayBuffer). Any help would be appreciated.

I'm imagining something like this:

worker = new Worker('workers.js');

var large_json = {};
for(var i = 0; i < 20000; ++i){
   large_json[i] = i;
   large_json["test" + i] = "string";
};

//How to make this call to use Transfer Objects? Takes approx 2 seconds to serialize this for me currently.
worker.webkitPostMessage(large_json);

Edit Report

Ok i did this i dont know if it's good or bad, ideal or worst way to do it. I just did it. in worker file

var data = e.data;
var string = String.fromCharCode.apply(null, new Uint16Array(data));
var objnow = JSON.parse(string);

in html file

function str2ab(str) {
   var buf = new ArrayBuffer(str.length*2); // 2 bytes for each char
   var bufView = new Uint16Array(buf);
   for (var i=0, strLen=str.length; i<strLen; i++) {
     bufView[i] = str.charCodeAt(i);
   }
   return buf;
 }
function stop() {
 var obj = {'cmd': 'stop', 'msg': 'Bye'};
 var str= JSON.stringify(obj);
 var arbfr = str2ab(obj);
 worker.postMessage(arbfr,[arbfr]);
}

And now it works i am able to send json object, transfer.

answered 2013-06-17T19:37:21.607

Web Workers - Transferable Objects for JSON

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