Yeah.

> The java.lang.Math.random() method returns a pseudorandom double type number greater than or equal to 0.0 and less than 1.0.

There's a built-in method for randomly selecting an int in a range. Use that.

Are you thinking of the Lodash random() function? Or Crypto.getRandomValues()?

floor is unnecessary. The cast does it for you. The problem is that a random double is not going to be evenly distributed into length equal parts unless length is a power of 2.