lodash/_createRange.js

define(['./_baseRange', './_isIterateeCall', './toNumber'], function(baseRange, isIterateeCall, toNumber) {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /**
   * Creates a `_.range` or `_.rangeRight` function.
   *
   * @private
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {Function} Returns the new range function.
   */
  function createRange(fromRight) {
    return function(start, end, step) {
      if (step && typeof step != 'number' && isIterateeCall(start, end, step)) {
        end = step = undefined;
      }
      // Ensure the sign of `-0` is preserved.
      start = toNumber(start);
      start = start === start ? start : 0;
      if (end === undefined) {
        end = start;
        start = 0;
      } else {
        end = toNumber(end) || 0;
      }
      step = step === undefined ? (start < end ? 1 : -1) : (toNumber(step) || 0);
      return baseRange(start, end, step, fromRight);
    };
  }

  return createRange;
});