Question

Let’s say I have an object of functions/values. I’m interested in overloading based on calling behavior.

For example, this block of code below demonstrates what I wish to do.

var main_thing = {
    initalized: false,
    something: "Hallo, welt!",
    something_else: [123,456,789],
    load: {
        sub1    : function() {
            //Some stuff
        },
        sub2    : function() {
            //Some stuff
        },
        all     : function() {
            this.sub1();
            this.sub2();
        }
    }
    init: function () {
        this.initalized=true;
        this.something="Hello, world!";
        this.something_else = [0,0,0];
        this.load(); //I want this to call this.load.all() instead.
    }
}

The issue to me is that main_thing.load is assigned to an object, and to call main_thing.load.all() would call the function inside of the object (the () operator). What can I do to set up my code so I could use main_thing.load as an access the object, and main_thing.load() to execute some code? Or at least, similar behavior.

Basically, this would be similar to a default constructor in other languages where you don’t need to call main_thing.constructor().

If this isn’t possible, please explain with a bit of detail.

Answer 1

Like Tom Tu said, functions are objects, and can have properties…

var main_thing = {

    // load will be set to the result of this anonymous function
    // which is a function with 2 extra properties set for the other functions        
    load: function() {
        // create what will be the load() function and store in "all"
        var all = function () {

               // When the function is actually executed these will have been assigned
               all.load1();
               all.load2();
            };

        // set 2 properties for sub load functions
        all.load1 = function() {};
        all.load2 = function() {};

        // return our function
        return all;
    }()
}

main_thing.load();
// or 
main_thing.load.load1();
main_thing.load.load2();