numeric array sort()

Question

Is this part from the book "Learning PHP, MySql and Javascript by. Robin Nixon" wrong?

numbers = [7, 23, 6, 74];

numbers.sort(function(a,b){return a - b});

output is 6,7,23,74

The book says:

If the anonymous function inside sort() returns a value greater than zero, the sort assumes a comes before b.

If the anonymous function inside sort() return a value less than zero, the sort assumes b comes before a.

The sort runs this function across all the values in the array to determine their order.

is this wrong? Because....

a here is 7
b here is 23

7 - 23 = -16 // a number less than zero. Book says it should b comes before a.

so the final output should be 74, 23, 7, 6

You know, you could just: try it out. Like in the above jsfiddle — TheZ
– TheZ, Commented Jul 6, 2012 at 18:28
Thats what im asking so the explanation from the book is wrong. Thanks guys. — Zzaaznedog Dafdf
– Zzaaznedog Dafdf, Commented Jul 6, 2012 at 18:30

andypaxo · Accepted Answer · 2012-07-06 18:29:47Z

5

It appears that it is wrong. From MDN:

If compareFunction(a, b) is less than 0, sort a to a lower index than b.

("Lower index" in this case would mean that a comes before b)

answered Jul 6, 2012 at 18:29

andypaxo

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David Kanarek · Accepted Answer · 2012-07-06 18:30:19Z

2

The output is correct, but the explanation is not. If the method returns < 0, a comes before b.

answered Jul 6, 2012 at 18:30

David Kanarek

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