JavaScript triple greater than

Question

I saw this syntax on another StackOverflow post and was curious as to what it does:

var len = this.length >>> 0;

What does >>> imply?

Answer 1

Ignoring its intended meaning, this is most likely where you'll see it used:

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>>> 0 is unique in that it is the only operator that will convert any type to a positive integer:

"string"         >>> 0 == 0
(function() { }) >>> 0 == 0
[1, 2, 3]        >>> 0 == 0
Math.PI          >>> 0 == 3

In your example, var len = this.length >>> 0, this is a way of getting an integer length to use to iterate over this, whatever type this.length may be.

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Similarly, ~~x can be used to convert any variable into a signed integer.