Anonymous Functions Clarification

Hi Mike,

It does make handling scope easier sometimes.

I also like anonymous functions because it makes reading the JavaScript easier.

For example, in jQuery if you fade out a DOM element, you might want to do something else after it disappears, such as set a flag value to be used elsewhere in your code. Creating a named function here would be unnecessary and arguably, harder to read in a large application.

For example, I would do something like this:

var paragraphHidden = false;

$("#myParagaph").fadeOut("slow", function() {

    paragraphHidden = true;

});

Although the code below would also work, I wouldn't normally do this, unless I thought my function setFlag might be used elsewhere in my application:

var paragraphHidden = false;

$("#myParagaph").fadeOut("slow", setFlag());

function setFlag() {
    paragraphHidden = true;
}

Hi Mike,

This article explains anonymous functions a little, i.e. "Not having to set a name for an anonymous function is just a convenience thing since in most cases the name of the function doesn’t really matter. Most of the time anonymous functions and named functions will both do any job perfectly well."

I also find anonymous functions useful when creating an object that contains methods/functions inside it, to do certain things.

A great example of this can be found in John Resig's excellent book. Below I've shown a modified version of his example from the book:

<script>
function Ninja() {
    var feints = 0;

    this.getFeints = function() {
        return feints;
    };

    this.feint = function() {
        feints++;
    };

}

var ninja_1 = new Ninja();
var ninja_2 = new Ninja();

ninja_1.feint(); // increments the fients variable inside the Ninja object

alert(ninja_1.getFeints()); // displays the number of feints, i.e. 1 feint
alert(ninja_2.getFeints()); // displays the number of feints in our second ninja, i.e. 0 feints


</script>