expert-m / react-split-testing

export default function weightedRandom(weights, randomSeed) { // randomSeed must be a string

  if (!randomSeed) {

    return -1

  }

  let totalWeight = 0

  for (let i = 0; i < weights.length; i++) {

    totalWeight += weights[i]

  }

  let random = getRandom(randomSeed) * totalWeight

  for (let i = 0; i < weights.length; i++) {

    if (random < weights[i]) {

      return i

    }

    random -= weights[i]

  }

  return -1

}