javascript function

array.sort(function(a, b){ return a -b ; } ) Sort the array array from small to large.

[11, 22, 586, 10, -58, 86].sort(function(a, b){ return a -b; } ) Return: [-58, 10, 11, 22, 86, 586]

The principle of sorting is to compare every two numbers, and then change the position of the elements in the array according to the positive or negative.
For example, in the first comparison, a is 11, b is 22, and then 11-22 is returned. The negative position remains unchanged.

array.sort(function(a, b){ return b - a ; } ) Sort the array in descending order.

[11, 22, 586, 10, -58, 86].sort(function(a, b){ return b - a ; } ) Returns: [586, 86, 22, 11, 10, -58]