Array property in class inheritance

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Fabio Scussel

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May 21, 2013, 10:23:31 AM5/21/13
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Hi, jsclass team,

Please consider the follow code:

var SuperClass = new JS.Class(
{
      content: [],
      add: function(letter) { this.content.push(letter); }
});

var ChildA = new JS.Class(SuperClass,
{
      add: function(letter) { this.content.push("A" + letter); }
});

var ChildB = new JS.Class(SuperClass,
{
     add: function(letter) { this.content.push("B" + letter); }
});

var a = new ChildA();
a.add("X"); a.add("Y"); a.add("Z");
var b = new ChildB();
b.add("X"); b.add("Y"); b.add("Z");
document.write(a.content);  //EXPECTED AX,AY,AZ
document.write("<br />");
document.write(b.content); //EXPECTED BX,BY,BZ

What I'm doing wrong? 
Thanks in advance for your reply

James Coglan

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May 21, 2013, 10:33:16 AM5/21/13
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On 21 May 2013 15:23, Fabio Scussel <fabios...@gmail.com> wrote:
var SuperClass = new JS.Class(
{
      content: [],
      add: function(letter) { this.content.push(letter); }
});

When you do this, there is only one array created and it is shared among all instances of the class via their prototype. That's why you're seeing state leak between objects. Try this instead:

var SuperClass = new JS.Class({
  initialize: function() {
    this.content = [];
  },
  add: function(letter) {
    this.content.push(letter);
  }
});

This creates a new array for every instance of the class. 

Fabio Scussel

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May 21, 2013, 11:53:00 AM5/21/13
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Thanks a lot. Now it's working as I expect!
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