What does [literal] in [array/object] mean?

Question

What does the following syntax mean:

1 in [1,2,3,5]

I know it doesn\'t search for 1 in the array. But what does it do?

I\'ve seen it u

Answer 1

'in' operator returns true if specified property exists in specified object; used in a loop it allows you to iterate over all properties of the object