Using bitwise OR 0 to floor a number

Question

A colleague of mine stumbled upon a method to floor float numbers using a bitwise or:

var a = 13.6 | 0; //a == 13

We were talking about it

Answer 1

This is truncation as opposed to flooring. Howard's answer is sort of correct; But I would add that Math.floor does exactly what it is supposed to with respect to negative numbers. Mathematically, that is what a floor is.

In the case you described above, the programmer was more interested in truncation or chopping the decimal completely off. Although, the syntax they used sort of obscures the fact that they are converting the float to an int.