How do modern browsers implement JS Array, in particular by adding elements?

Question

By this I mean when calling .push()an Array object, and JavaScript increases the capacity (by the number of elements) of the underlying “array”. Also, if there is a good resource for finding such information for JS, it would be useful to include it.

change

It seems that the JS array is like an object literal with special properties. However, I am interested in a lower level of detail - how browsers implement this in their JS machines.

Answer 1

qurstion. - JS . , Tamarin , , , .

Answer 2

. . @Samuel Neff :

http://news.qooxdoo.org/javascript-array-performance-oddities-characteristics

http://jsperf.com/array-popuplation-direction

JavaScript , . length "0", "1", "2" .. .push() , :

ary[ ary.length++ ] = the_new_element; // set via hash

a >

Answer 3

Javascript does include a mechanism for declaring the length of your array, for example:

var foo = new Array(3);
alert(foo.length); // alerts 3

But since arrays are dynamic in javascript, there is no reason for this, you do not need to manually allocate your arrays. In the above example, an array of fixed length is not created, it simply initializes it with three undefined elements.

// Edit: I am either reading your question incorrectly, or you changed it, sorry, I do not think that this is what you asked for.