// original gist
const shuffleArray = arr => arr.sort(() => Math.random() - 0.5);

// fully random by @BetonMAN
const shuffleArray = arr => (
  arr
    .map(a => [Math.random(), a])
    .sort((a, b) => a[0] - b[0])
    .map(a => a[1]);
);

shuffleArray([1, 2, 3]) //[3, 1, 2]