Differences of random entire functions
while checking some code I found the following random number generator function:
function randomInt(min, max) {
return min ? min : min = 0,
max ? max : max = 1,
0 | Math.random() * (max - min + 1) + min
}
Comparing it to the equivalent function on MDN :
// Returns a random integer between min (included) and max (excluded)
// Using Math.round() will give you a non-uniform distribution!
function getRandomInt(min, max) {
return Math.floor(Math.random() * (max - min)) + min;
}
I understand that the first one creates and an integer with max
included and that it checks the values or assigns default values to them min
and max
, but I don't understand how it returns an integer and not a float without a method Math.floor()
.
Is this achieved with an expression 0 | Math.random() * (max - min + 1) + min
? If so, how?
The result is converted to an integer with an operator |
that is bitwise OR . From MDN, the first step in calculating the result:
Operands are converted to thirty-two bit integers and expressed as a series of bits (zeros and ones).
And since you are ORing from 0, this operation will not change the value of the result (other than the previously mentioned conversion).
0 |
- bitwise operation.
It does not affect the value (ORing with a zero returns the original value), but like all bitwise operations, it truncates the integer (bitwise operations don't make sense for non-integers).