如何从函数中获取[[boundthis]] [英] How to get [[boundthis]] from function

问题描述

我需要你的帮助。

我有2个功能：

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;
},

这个：

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);
},

如何从函数resizeListener获取属性[[BoundThis]]而不执行。

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

推荐答案

你做不到。 [[BoundThis]] 是绑定的内部属性功能对象。它不能以编程方式访问。

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

您可以通过控制台检查对象来查看它，但要在程序逻辑中使用它，您需要编写自己的 bind 版本，将此值公开为属性。

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.

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