Fastest way to convert JavaScript NodeList to Array?

Question

Previously answered questions here said that this was the fastest way:

//nl is a NodeList
var arr = Array.prototype.slice.call(nl);

In benc

Answer 1

faster and shorter :

// nl is the nodelist
var a=[], l=nl.length>>>0;
for( ; l--; a[l]=nl[l] );

Answer 2

Here are charts updated as of the date of this posting ("unknown platform" chart is Internet Explorer 11.15.16299.0):

From these results, it seems that the preallocate 1 method is the safest cross-browser bet.

Answer 3

NodeList.prototype.forEach = Array.prototype.forEach;

Now you can do document.querySelectorAll('div').forEach(function()...)

Answer 4

This is the function I use in my JS:

function toArray(nl) {
    for(var a=[], l=nl.length; l--; a[l]=nl[l]);
    return a;
}

Answer 5

Some optimizations:

• save the NodeList's length in a variable
• explicitly set the new array's length before setting.
• access the indices, rather than pushing or unshifting.

Code (jsPerf):

var arr = [];
for (var i = 0, ref = arr.length = nl.length; i < ref; i++) {
 arr[i] = nl[i];
}

Answer 6

The second one tends to be faster in some browsers, but the main point is that you have to use it because the first one is just not cross-browser. Even though The Times They Are a-Changin'

@kangax (IE 9 preview)

Array.prototype.slice can now convert certain host objects (e.g. NodeList’s) to arrays — something that majority of modern browsers have been able to do for quite a while.

Example:

Array.prototype.slice.call(document.childNodes);