react-experiment-hoc/src/weighted.js

Simple hoc to provide a/b-test features.

export default function(weights) {
  var totalWeight = 0,
      i,
      random;

  for (i = 0; i < weights.length; i++) {
    totalWeight += parseInt(weights[i]);
  }

  random = Math.random() * totalWeight;

  for (i = 0; i < weights.length; i++) {
    if (random < parseInt(weights[i])) {
      return i;
    }

    random -= parseInt(weights[i]);
  }

  return -1;
};