access outer "this" in Javascript sort method

Question

I have this code:

function some_object(...) {    this.data = {...};     this.do_something = function(...) {       var arr = [...];        arr.sort(function (a, b) {          return this.data[a] - this.data[b];       });      } } 

However it's not working I think because this cannot be accessed in sort - another this is seen there for some reason, not the this of enclosing outer object.

What to do? thanks

Answer 1

The different this is because the the anonymous function (its own closure) called by arr.sort calls the function with this being set to a different item than your main object. In an Array.sort, I am not actually sure what this is set to, but it is probably the Array you are sorting. A normal work around in this situation is to use another variable:

function some_object(...) {    var so = this; // so = current `this`    this.data = {...};     this.do_something = function(...) {       var arr = [...];        arr.sort(function (a, b) {          return so.data[a] - so.data[b];       });      } }