Scope of function called after deffered resolved

Question

I have a function that need to wait for another function to be done before it can be called so I try to use jquery deferred. So for example:

firstFunction().done(secondFunction)

But secondFunction has in its scope some usages of this keyword so when it is called via done it don't have access for proper this property. For more those functions are placed in different files. Is there a way to call secondFunction with proper this property?

Answer 1

Yes, you can bind the function to the correct context.

For IE9 and up you can use native Javascript for this, namely Function.prototype.bind

firstFunction().done(secondFunction.bind(this));

If for some reason you're supporting IE8 then you either need to polyfill it (there's a recipe for that on the mdn page linked above) or you can use underscore's bind which should be available since it's required by backbone.

firstFunction().done(_.bind(secondFunction, this));