How does Javascript's native sort method work?

Question

[1, false, 10, "b", 3, "33", ":", "R", "^"].sort()

Yields the following sort:

[1, 10, 3, "33", ":", "R", "^", "b", false]

Can anyone explain how the sort method works? I'm guessing that it must be translating everything into ASCII.

The plot thickens when I do this

[1, false, 10, "b", 3, "33", ":", "R", "^"].sort(function(a,b) {return b-a})

Outputs the following:

[10, 1, false, "b", "33", 3, ":", "R", "^"]

Any method to this madness?

The default sort order is according to string Unicode code points. — nem035
– nem035, Commented Dec 9, 2015 at 17:19
developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… — house9
– house9, Commented Dec 9, 2015 at 17:20
Why can't you add some info on why you think it looks like madness e.g. show that it's not what you'd have thought it was — barlop
– barlop, Commented Dec 9, 2015 at 17:20
Totally. String unicode makes sense, but I thought that the native .sort and the sort(fn (a,b,) {return b-a}) would return the same order. Instead, the order is not even flipped in the second example. It is rearranged with regards to 10,1, and false. — Anthony Chung
– Anthony Chung, Commented Dec 9, 2015 at 21:48

TbWill4321 · Accepted Answer · 2015-12-09 17:20:09Z

6

From MDN:

If compareFunction is not supplied, elements are sorted by converting them to strings and comparing strings in Unicode code point order.

And:

If compareFunction is supplied, the array elements are sorted according to the return value of the compare function.

answered Dec 9, 2015 at 17:20

TbWill4321

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