Javascript OOP - accessing the inherited property or function from a closure within a subclass -

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i using javascript inheritance helper provided here: http://ejohn.org/blog/simple-javascript-inheritance/

i have following code, , have problem accessing inherited property or function closure within subclass illustrated below. new oop javascript code , appreciate advice. suppose within closure, context changes jquery (this variable) hence problem. appreciate comments.

thanks, -a

ps - using jquery 1.5

     var users = class.extend({                 init: function(names){this.names = names;}             });             var homeusers = users.extend({                 work:function(){  //                alert(this.names.length); // prints  //                var names = this.names;  // if make local alias works                     $.map([1,2,3],function(){                         var newname = this.names.length; //error this.names not defined.                         alert(newname);                      });                  }             });  var users = new homeusers(["a"]); users.work();

this in inner function

    function(){         var newname = this.names.length;         alert(newname);      }

is not same this in outer function.

work: function(){      $.map([1,2,3],function(){         var newname = this.names.length;         alert(newname);      }); }

there many ways people work around this:

store reference outer function's this variable

work: function(){      var = this;     $.map([1,2,3],function(){         var newname = that.names.length;         alert(newname);      }); }

as see, that being used instead of this.

use jquery's $.proxy

work: function(){      $.map([1,2,3],$.proxy(function(){         var newname = this.names.length;         alert(newname);      }, this)); }

what $.proxy creates function calls function passed in (in case, inner function), explicitly set context of function (this) second arguments.

use function.prototype.bind

work: function(){      $.map([1,2,3],function(){         var newname = this.names.length;         alert(newname);     }.bind(this)); }

it works jquery's $.proxy, in one, call bind method of function.

it isn't supported on browsers, there javascript implementation of function.prototype.bind on mdc. can use it.

this in confusing keyword, , if want learn more this, @ this.


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