How .sort () work in JavaScript? [duplicate]

Question

Possible Duplicate:
Javascript Array.sort implementation?

I want to know how .sort() works in JavaScript. What algorithm does it use?

function sortNumber(a, b) {
   return a-b;
}

var n = ["1", "5", "40", "2", "9", "3"];
document.write(n.sort(sortNumber));

I fixed the formatting for you. Please use the preview pane next time. — Lightness Races in Orbit
– Lightness Races in Orbit, Commented Apr 20, 2011 at 11:22
"How .sort() working" in what way? It sorts. The precise algorithm is probably implementation-defined. What else do you want to know? — Lightness Races in Orbit
– Lightness Races in Orbit, Commented Apr 20, 2011 at 11:22
hi tomalak ,thanks for doing formatting. I want to know which algo is used on .sort() function. — Hitesh Prajapati
– Hitesh Prajapati, Commented Apr 20, 2011 at 11:24

Community · Accepted Answer · 2017-05-23 10:28:08Z

2

This question was answered here.

Mozilla uses merge sort, Webkit uses selection sort, and IE is closed-source so hard to tell.

The language specification states no requirement on what algorithm an implementation uses, and your code shouldn't really care about it too much.

edited May 23, 2017 at 10:28

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answered Apr 20, 2011 at 11:28

Lightness Races in Orbit

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Comments

pepkin88 · Accepted Answer · 2011-04-20 12:05:21Z

0

Number of comparisons for 100 element test array:

Safari 5 - 541
Opera 11.10 - 586
Firefox 4 - 601
IE 9 - 618
Chrome 9 - 783

And for 1000 element test array:

Safari 5 - 8700
Firefox 4 - 8998
Opera 11.10 - 9137
IE 9 - 11055
Chrome 9 - 11536

It does not describe an algorithm but still shows some interesting data.

edited Apr 20, 2011 at 12:05

answered Apr 20, 2011 at 11:59

pepkin88

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Comments

KebdnK · Accepted Answer · 2011-04-20 11:25:57Z

-1

in Firefox 4 the elements are converted into Numbers and sorted this way. In your case this is ascending order.

I didn't test it in other browsers so far.

answered Apr 20, 2011 at 11:25

KebdnK

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1 Comment

pepkin88 Over a year ago

Elements are not converted into numbers. Elements don't change. Expression a-b calculates numerical result, that's all.

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