weighted-random-object/build/weighted-random-object.js

Get a weighted random object from an array of objects.

"use strict";

/**
 * Get a weighted random object from an array of objects with a weight property.
 *
 * The objects should have a property with key 'weight' and a value that is a number.
 */
module.exports = function (objects) {
  var totalWeight = objects.reduce(function (agg, object) {
    return agg + object.weight;
  }, 0);
  var randomNumber = Math.random() * totalWeight;
  var weightSum = 0;
  return objects.find(function (object) {
    weightSum += object.weight;
    return randomNumber <= weightSum;
  });
};