Advantages to using bind versus using a local reference to this?

Question

Are there advantages or differences to using _.bind versus using a local reference to this?

Here's a very simplified example: doAdd is an example of a local function that needs to effect a property on the parent object; it's ultimately run as a callback function inside doSomethingThenCallback. Option A vs. option B:

var obj = {
    num: 1,

    // Option A
    add_A: function() {
        function doAdd(){
            this.num++;
        }
        // Make the "this" in the function refer to the parent object
        doAdd = _.bind(doAdd, this);
        doSomethingThenCallback(doAdd);
    },

    // Option B
    add_B: function() {
        // Save a local reference to "this"
        var o = this;
        function doAdd(){
            o.num++;
        }
        doSomethingThenCallback(doAdd);
    }
}

if you need lexical this than bind it. it is better practice, it's cleaner and less prone to errors. if you need reference to both 'this' then assign it to variable. — webduvet, Jul 31 '15 at 15:25
@webduvet Can you elaborate as an answer? Would be good to see what kind of errors it helps prevent. — Luke, Jul 31 '15 at 15:28
Your `_.bind(doAdd, this)` does nothing useful, `_.bind` returns the bound function, it doesn't modify it in-place. — mu is too short, Jul 31 '15 at 17:17
See http://stackoverflow.com/questions/6397096/function-bind-vs-closure-in-javascript-how-to-choose. — , Jul 31 '15 at 18:22
You left out an option that seems to be fairly common these days: you can provide a second context argument to `doSomethingThenCallback` so that it can call the callback with whatever `this` you need using [`Function.prototype.apply`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/apply). The choice is mostly a matter of personal taste, cases where it matters are fairly rare. — mu is too short, Jul 31 '15 at 21:36

Advantages to using bind versus using a local reference to this?

0 Answers0