CODEWITHSUNDEEP
javascriptjquery
user537339
user537339

Reputation: 1831

What exactly does $(...).map() return?

Given this:

<a href="1">1</a>
<a href="2">2</a>

Here is a function to return an array of href values:

e = $('a').map(function(v) { return $(this).attr('href'); });
console.log(e);

But it gives

["1", "2", prevObject: x.fn.x.init[2], context: document, jquery: "1.10.2", constructor: function, init: function…]

How can I modify this to only return a raw array ["1", "2"]?

Upvotes: 17

Views: 2456

Answers (1)

Andreas Louv
Andreas Louv

Reputation: 47099

It is because jQuery.fn.map returns a new jQuery Object, you should use jQuery.fn.get to get an array:

var a = $('a').map(function(v, node) { 
    // v is the index in the jQuery Object, 
    // you would maybe like to return the domNode or the href or something: 
    // return node.href;

    return v; 
}).get(); // <-- Note .get() converts the jQuery Object to an array

Micro optimization:

If you look at the source code for jQuery.fn.get you can see that it points you to jQuery.fn.toArray:

function ( num ) {
    return num == null ?

        // Return a 'clean' array
        this.toArray() :

        // Return just the object
        ( num < 0 ? this[ this.length + num ] : this[ num ] );
}

So you can also call:

$('a').map(...).toArray();

Upvotes: 31

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