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

Just for the fun of it:

var plusOrMinus = [-1,1][Math.random()*2|0];  

or

var plusOrMinus = Math.random()*2|0 || -1;

But use what you think will be maintainable.