postMessage

JavaScript performance comparison

Revision 3 of this test case created by David Bruant

Info

echoSetTimeout is used when features aren't available. For instance: - No workers (IE6-9, 10?) - No MessageChannel (FF<=4)

Preparation code

<script>
  var payload = {
    shortString: 'test',
    simple: {
      foo: "bar",
      arr: []
    }
  };
 
  var echoSetTimeout = (function() {
    return function(msg, cb) {
      setTimeout(cb, 0);
    }
  })();
 
  var echoWorker = (function() {
    var code = 'onmessage = function(e) { postMessage(e.data) };';
    var blobBuilder = window.BlobBuilder || window.WebKitBlobBuilder || window.MozBlobBuilder;
    if(!blobBuilder) {
      return echoSetTimeout;
    }
    var bb = new (blobBuilder)();
    bb.append(code);
 
    var blobURL = (window.URL || window.webkitURL || window.mozURL).createObjectURL(bb.getBlob());
    var worker = new Worker(blobURL);
   
    return function(msg, cb) {
      worker.onmessage = cb;
      worker.postMessage(msg);
    };
  })();
 
  var echoIFramePostMessage = (function() {
    var iframe = document.createElement('iframe');
    window.onload = function() {
      iframe.style.display = 'none';
      document.body.appendChild(iframe);
      iframe.contentDocument.write('<html><head><script>onmessage = function(e) { e.source.postMessage(e.data, "*") };<'+'/script><'+'/head><'+'/html>');
    };
   
    return function(msg, cb) {
      window.onmessage = cb;
      iframe.contentWindow.postMessage(msg, '*');
    };
  })();
 
  var echoPostMessage = (function() {
    return function(msg, cb) {
      async = false;
      window.onmessage = cb;
      window.postMessage(msg, '*');
      async = true;
    };
  })();
 
  var echoMessageChannel = (function() {
    if(!window.MessageChannel)
      return echoSetTimeout;
 
    var mc = new MessageChannel();
    return function(msg, cb){
      mc.port1.onmessage = cb;
      mc.port2.postMessage(msg);
    };
  })();
</script>

Test runner

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Testing in unknown unknown
Test Ops/sec
Worker shortString
// async test
echoWorker(payload.shortString, function resolve() {
  deferred.resolve();
});
pending…
sameWindowPostmessage shortString
// async test
echoPostMessage(payload.shortString, function resolve() {
  deferred.resolve();
});
 
pending…
setTimeout shortString
// async test
echoSetTimeout(payload.shortString, function resolve() {
  deferred.resolve();
});
pending…
MessageChannel shortString`
// async test
echoMessageChannel(payload.shortString, function resolve() {
  deferred.resolve();
});
pending…
iframe shortString
// async test
echoIFramePostMessage(payload.shortString, function resolve() {
  deferred.resolve();
});
pending…

Compare results of other browsers

Revisions

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1 comment

strager commented :

Degrading down to setTimeout is really annoying, as it's hard to compare browsers. It's better to fail than to degrade in a performance test like this.

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