Maintaining the reference to “this” in Javascript when using callbacks and closures

Question

I find myself assigning \"this\" to a variable so I can easily use it in callbacks and closures.

Is this bad practice? Is there a better way of referring back to the

Answer 1

You could create a proxy for the callback with:

var createProxy = function(fn, scope) {
  return function () {
    return fn.apply(scope, arguments);
  }; 
};

Using this, you could do the following:

db.User.findById('ABCD', createProxy(function(err, user)) {
  this.foo(user);
}, this));

jQuery does something similar with: $.proxy

And, as others have noted using bind, have a look here if compatibility is an issue:

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/bind#Compatibility