paper.js和javascript'this'混淆

Question

Hi I am creating a Cabinet object in javascript and I am trying to access the objects property inside paper.js' onFrame function... But when I use 'this' inside the onFrame function I can not access the object property:

function Cabinet(){
    this.spine = new Path({x:0, y:0});
    this.draw();    
    return this;
}

Cabinet.prototype = {
  draw:function(){
    view.onFrame = function(event) {
      this.spine // trying to access Cabinet object but this is not referring to    Cabinet object
    }
  }
}

How can I achieve this?

Answer 1

Simply save the value of this in a variable:

Cabinet.prototype = {
  draw:function(){
    var cab = this;
    this.spine.onFrame = function(event) {
      cab.spine // ...
    }
  }
}

Answer 2

You could bind the function so that this becomes a reference to the Cabinet object.

Cabinet.prototype = {
  draw: function() {
    view.onFrame = function(event) {
      this.spine;
    }.bind(this);
  }
}