maybe.js

// Returns true about 50% of the time, false about 50% of the time.
export default const maybe = () => Math.random() < .5;

// This should be closer to .5 the more iterations you run.
export const tester = iterations => {
  let yes = 0;
  for (let i = 0; i < iterations; i++) maybe() && yes++;
  return yes/iterations;
}