JavaScript Random Positive or Negative Number

Question

I need to create a random -1 or 1 to multiply an already existing number by. Issue is my current random function generates a -1, 0, or 1. What is the most efficient way of doing

Answer 1

I've always been a fan of

Math.round(Math.random()) * 2 - 1

as it just sort of makes sense.

• Math.round(Math.random()) will give you 0 or 1

• Multiplying the result by 2 will give you 0 or 2

• And then subtracting 1 gives you -1 or 1.

Intuitive!