123456789101112131415161718192021222324252627282930313233
// xorshift128 variation of https://en.wikipedia.org/wiki/Xorshift
const baseSeeds = [123456789, 362436069, 521288629, 88675123]
const xor = seed => {  let [x, y, z, w] = baseSeeds
  const random = () => {    const t = x ^ (x << 11);    [x, y, z] = [y, z, w]    w = w ^ (w >> 19) ^ (t ^ (t >> 8))    return w / 0x7FFFFFFF  }
  const seeder = () => Math.round(random() * 1e16)
  const setSeeds = seed => {    [x, y, z, w] = baseSeeds.map(i => i + seed);    [x, y, z, w] = [seeder(), seeder(), seeder(), seeder()]  }
  setSeeds(seed)
  return {    random: () => random(),    reseed: setSeeds,    getState: () => [x, y, z, w],    setState: seeds => ([x, y, z, w] = seeds)  }}
module.exports = xor