random.js

var baseRandom = require('../internal/baseRandom'),
    isIterateeCall = require('../internal/isIterateeCall');

/* Native method references for those with the same name as other `lodash` methods. */
var nativeMin = Math.min,
    nativeRandom = Math.random;

/**
 * Produces a random number between `min` and `max` (inclusive). If only one
 * argument is provided a number between `0` and the given number is returned.
 * If `floating` is `true`, or either `min` or `max` are floats, a floating-point
 * number is returned instead of an integer.
 *
 * @static
 * @memberOf _
 * @category Number
 * @param {number} [min=0] The minimum possible value.
 * @param {number} [max=1] The maximum possible value.
 * @param {boolean} [floating] Specify returning a floating-point number.
 * @returns {number} Returns the random number.
 * @example
 *
 * _.random(0, 5);
 * // => an integer between 0 and 5
 *
 * _.random(5);
 * // => also an integer between 0 and 5
 *
 * _.random(5, true);
 * // => a floating-point number between 0 and 5
 *
 * _.random(1.2, 5.2);
 * // => a floating-point number between 1.2 and 5.2
 */
function random(min, max, floating) {
  if (floating && isIterateeCall(min, max, floating)) {
    max = floating = null;
  }
  var noMin = min == null,
      noMax = max == null;

  if (floating == null) {
    if (noMax && typeof min == 'boolean') {
      floating = min;
      min = 1;
    }
    else if (typeof max == 'boolean') {
      floating = max;
      noMax = true;
    }
  }
  if (noMin && noMax) {
    max = 1;
    noMax = false;
  }
  min = +min || 0;
  if (noMax) {
    max = min;
    min = 0;
  } else {
    max = +max || 0;
  }
  if (floating || min % 1 || max % 1) {
    var rand = nativeRandom();
    return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand + '').length - 1)))), max);
  }
  return baseRandom(min, max);
}

module.exports = random;