Question

Suppose I have an object, with some properties and methods:

var Form = {
    name: 'sign-up',

    show: function() {...},
    hide: function() {...},
    validate: function() {...},
    updateCurrency: function() {...},
    handleCheckBox: function() {...}
}

Now I want to call different methods when certain events happen in my form like so:

$('#country-select').bind('change', function() {
    Form.updateCurrency();
});

$("input[type='checkbox']").bind('change', function() {
    Form.handleCheckBox();
});

I have a lot of these event listeners, and frankly, I find them ugly listed out one by one like that and not tied directly to the object they relate to. Is there a more elegant way of encapsulating them within my object literal Form? Is there a best practice?

Answer 1

I like @gillesc answer, it’s on the right tracks.
However, I think we can do better.

The main issue with @gillesc answer is that its missing the dynamic aspect of things (event handlers for instance), also it forces your to define ugly callback functions.

So heres how I think you should solve your problem.

// Test object
var testObj = {
    // Our event handlers. 
    // Notice how we must only define the callback function name here. 
    // Not the function itself. The callback function must be defined in testObj.
    handlers: {
        '#form submit': 'onSubmit'
    },
    // Method that will register all handlers to some selector
    registerHandlers: function() {
        var that = this;
        // Go through the handlers list.
        $.each(this.handlers, function(k, v) {
            // Parsing the event to two different parts. 
            // 1. trigger event
            // 2. selector
            var split = k.split(" "),
                el = split[0],
                trigger = split[1];

            // Delegating the trigger to selector
            $(document).delegate(el, trigger, that[v]);
        });
    },
    // Our actual callback function
    onSubmit: function(evt) {
        evt.preventDefault();
        alert("submit");
    }
};

How would it all work? Thats easy! We just need to call testObj.registerHandlers().

JSFiddle demo