.gitignore

## .gitignore
jspm_packages

## README.md

      
          Raw
        
        
              README.md
            
          
    "Not optimized: Bad value context for arguments value"
Adding a property to one function, but not all functions, causes Not optimized flag on function containing Function.prototype.apply.
Cause
"V8 only recognizes monomorphic .apply call-sites" - @mraleph
Example
See example.js
Fixes

Don't attach properties to functions
Copy arguments to an array.  See https://github.com/GoogleChrome/devtools-docs/issues/53#issuecomment-51941358
Provide a monomorphic .apply call-site (see fix.js)

Test in node
node --trace_opt --trace_deopt example.js | grep "failed to optimize dispatch"

Test in browser
jspm install
http-server  # open http://localhost:8080/


## config.js
System.config({
  baseURL: "/",
  defaultJSExtensions: true,
  transpiler: "none",
  paths: {
    "github:*": "jspm_packages/github/*",
    "npm:*": "jspm_packages/npm/*"
  },

  map: {
    "assert": "github:jspm/nodelibs-assert@0.1.0",
    "github:jspm/nodelibs-assert@0.1.0": {
      "assert": "npm:assert@1.3.0"
    },
    "github:jspm/nodelibs-process@0.1.2": {
      "process": "npm:process@0.11.2"
    },
    "github:jspm/nodelibs-util@0.1.0": {
      "util": "npm:util@0.10.3"
    },
    "npm:assert@1.3.0": {
      "util": "npm:util@0.10.3"
    },
    "npm:inherits@2.0.1": {
      "util": "github:jspm/nodelibs-util@0.1.0"
    },
    "npm:process@0.11.2": {
      "assert": "github:jspm/nodelibs-assert@0.1.0"
    },
    "npm:util@0.10.3": {
      "inherits": "npm:inherits@2.0.1",
      "process": "github:jspm/nodelibs-process@0.1.2"
    }
  }
});

## example.js
var assert = require('assert');

// the following line causes "failed to optimize dispatch: Bad value context for arguments value" notification
dispatchOne.$ = 'Causes Bad value context for arguments value';

// the following line, if uncommented, will allow optimization
//dispatchTwo.$ = 'Allows optimization';

var callbacks = [dispatchOne, dispatchTwo];

for(var i=0;i<2000000; i++) {
  dispatch(1,2,3,4,5);
}

function dispatch() {
  var i = callbacks.length;
  while (i--) {
    callbacks[i].apply(null, arguments);
  }
}

function dispatchOne() {
  assert(arguments.length == 5);
}

function dispatchTwo() {
  assert(arguments.length > 4);
}

## example2.js
var assert = require('assert');

var callbacks = [dispatchOne, dispatchTwo.bind(0)];

for(var i=0;i<2000000; i++) {
  dispatch(1,2,3,4,5);
}

function dispatch() {
  var i = callbacks.length;
  while (i--) {
    callbacks[i].apply(null, arguments);
  }
}

function dispatchOne() {
  assert(arguments.length == 5);
}

function dispatchTwo() {
  assert(arguments.length > 4);
}

## fix.js
var assert = require('assert');

// the following line causes "failed to optimize dispatch: Bad value context for arguments value" notification
dispatchOne.$ = 'Causes Bad value context for arguments value';

// the following line, if uncommented, will allow optimization
//dispatchTwo.$ = 'Allows optimization';

var callbacks = [dispatchOne.bind(null), dispatchTwo];

for(var i=0;i<2000000; i++) {
  dispatch(1,2,3,4,5);
}

function dispatch() {
  var i = callbacks.length;
  while (i--) {
    callbacks[i].bind(0)    // ensures "monomorphic .apply call-sites"
      .apply(0, arguments);
  }
}

function dispatchOne() {
  assert(arguments.length == 5);
}

function dispatchTwo() {
  assert(arguments.length > 4);
}

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>EventsSpeedTests</title>
  <style>
  button {
    padding: .5em 1em;
    display: block;
    text-align: center;
    margin-top: 5px;
    width: 200px;
  }
  </style>
</head>

<body id="home">

  <h1>De-opt Test</h1>

  <script src="jspm_packages/system.js"></script>
  <script src="config.js"></script>
  <script>

    addButton('example');
    addButton('example2');
    addButton('fix');

    function addButton(name) {
      var element = document.createElement("button");
      element.innerHTML = name;
      element.onclick=function(){
        console.log('start',name);
        var start = new Date().getTime();
        System.import('./'+name+'.js').then(function () {
          var time = new Date().getTime() - start;
          console.log('end',name, time, 'ms');
        });
      }
      document.body.appendChild(element);
    }
  </script>

</body>
</html>

## package.json
{
  "jspm": {
    "directories": {},
    "dependencies": {
      "assert": "github:jspm/nodelibs-assert@^0.1.0"
    }
  }
}