How to call a method inside a javascript object

Question

I\'m just learning about how to best organize my javascript code, and I had a question regarding this small piece of code I wrote:

var reportsControllerIndex = {         


        

Answer 1

You want to store the this binding in a variable.

drawMap: function() {
    var _this = this;
    $.getJSON('/reports.json', function(data) {
        _this.plotMapPoints(data);         
    });
}

Answer 2

plotMapPoints: function(data) {
    //plots points
}.bind(this)

when defining your function you can just add .bind(this) to set the correct context for that function.

Answer 3

You can write it likes this:

var reportsControllerIndex = new function () {

    var self = this;

    self.plotMapPoints = function (data) {
        //plots points
    },

    self.drawMap = function () {
        $.getJSON('/reports.json', function (data) {
            self.plotMapPoints(data);         
        });
    },

    self.run = function () {
        self.drawMap();
    }
};

This class will works as same as you did, and you can still call the class method by:

reportsControllerIndex.run()

In this paradigm, I defined self pointing to the class itself, so that you can call self wherever you want in the class.

---

Farther, this paradigm can solve the this problem in the function that you bring as callback to another funciton:

plotMapPoints: function(data) {
    console.log(this);
    // Need a this referring to the class itself
    // It's inconvenient to bring this as parameter
},

Answer 4

Late answer, but jQuery has a method called jQuery.proxy() that is made for this purpose. You pass it the function along with the value of this you want to retain, and it will return a function that ensures this is correct.

This way you don't need to define a variable.

drawMap: function() {
    $.getJSON('/reports.json', $.proxy(function(data) {
        this.plotMapPoints(data);         
    }, this));
}

Answer 5

You need to use a variable reference to this outside the getJSON function. getJSON sets the context of the callback within jquery.

Like this:

var self = this;
$.getJSON('/reports.json', function(data) {
    self.plotMapPoints(data);         
});