I need your help.
I have 2 functions:

addMoveListeners: function(e) {
  e = e || window.event;
  // Binging context to function move
  moveListener = MYAPP.move.bind(e.target.parentElement);
  //
  if (e.target.classList.contains('move')){
    document.addEventListener('mousemove', moveListener, false);
    document.addEventListener('mouseup', MYAPP.removeListener, false);
  }
  resizeListener = MYAPP.resize.bind(e.target.parentElement);
  if (e.target.classList.contains('resize')){
    document.addEventListener('mousemove', resizeListener, false);
    document.addEventListener('mouseup', MYAPP.removeListener, false);
  }
  return false;
},

and this:

removeListener: function(e){
  e = e || window.event;
  //Here I want get element from function
  console.dir(resizeListener);
  // Function stores it in [[BoundThis]]
  document.removeEventListener('mousemove', resizeListener, false);
  document.removeEventListener('mouseup', MYAPP.removeListener, false);
  document.removeEventListener('mousemove', moveListener, false);
  document.removeEventListener('mouseup', MYAPP.moveListener, false);
},

How can I get property [[BoundThis]] from function resizeListener without execution.

I need your help.
I have 2 functions:

addMoveListeners: function(e) {
  e = e || window.event;
  // Binging context to function move
  moveListener = MYAPP.move.bind(e.target.parentElement);
  //
  if (e.target.classList.contains('move')){
    document.addEventListener('mousemove', moveListener, false);
    document.addEventListener('mouseup', MYAPP.removeListener, false);
  }
  resizeListener = MYAPP.resize.bind(e.target.parentElement);
  if (e.target.classList.contains('resize')){
    document.addEventListener('mousemove', resizeListener, false);
    document.addEventListener('mouseup', MYAPP.removeListener, false);
  }
  return false;
},

and this:

removeListener: function(e){
  e = e || window.event;
  //Here I want get element from function
  console.dir(resizeListener);
  // Function stores it in [[BoundThis]]
  document.removeEventListener('mousemove', resizeListener, false);
  document.removeEventListener('mouseup', MYAPP.removeListener, false);
  document.removeEventListener('mousemove', moveListener, false);
  document.removeEventListener('mouseup', MYAPP.moveListener, false);
},

How can I get property [[BoundThis]] from function resizeListener without execution.

• javascript

• 1 what is BoundThis, you mean this? – Prabhu Murthy Commented Dec 10, 2014 at 12:51
• 1 console.dir(function) give me this - [[BoundThis]]: div.note.note2 – trunkovich Commented Dec 10, 2014 at 13:00
• 3 @unikorn: the OP has called Function.prototype.bind on the handler -- I suspect the OP wants to get the this value that has been bound to the function. – Qantas 94 Heavy Commented Dec 10, 2014 at 13:08

1 Answer 1

You cannot. [[BoundThis]] is an internal property of bound function objects. It is not programmatically accessible.

You might be able to view it with inspection of the object via console, but to use it in your program logic you will need to write your own version of bind that exposes this value as a property.