Array.sort() 比较函数

Question

The code I found to sort a list of numbers by ascending order is:

arr.sort((a,b) => a-b);

I don't understand how the compare function works. What if you do arr.sort((a,b) => a+b)?

Answer 1

The sort function uses the sign of the value returned by the comparator :

• Positive means A > B.
• Negative means A < B.
• Zero means A == B.

So a - b is just a neat shorthand which fulfills those cases.