A peek into JavaScript’s Array.prototype.map and jQuery.map


The map function comes from JavaScript’s functional programming roots: it applies a function to every array element and returns a new array of the results without mutating the original array. So lets look at the native JS and jQuery map implementations.


The signature for the native JS implementation is:

The callback is the transforming function that changes elements of array into new elements while thisObject will be this inside the callback (some cool applications exist). Most browsers allow Array.protototype.map  (support got added in JavaScript 1.6) however a few browsers still do not.

jQuery’s map

The signature for the jQuery implementation is:

The array and callback parameters mean the same as above while the arg parameter allows you to send in extra arguments into the function ( I still haven’t found a use for this yet).  Unfortunately this inside the callback refers to the Global object (Window); if you need…

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