Wilson Page

I have often seen references to ‘map’ in javascript and not really taken the time to fully understand what it means.

What is map?

map loops over an array and runs a function on each element in the array. What ever you return from that function will replace the element in the current position. The output of the $.map() is the new array after each element has been manipulated though your ‘iterator’ function.

Map is available natively in later versions of Javascript (IE9+) but not in older browsers, so in the meantime we have to use jQuery’s $.map() method to ensure cross browser compatibility.

Basic Example

var result = $.map( [1,2,3,4], function (a) { 
  return a * 2; 
});

// result => [2,4,6,8]

Working Examples:

http://jsfiddle.net/WilsonPage/KjPM6/5/

Hope this was a nice introduction to map and you can see how useful this could be in your own projects :)