_createRange.js 864 Bytes
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
var baseRange = require('./_baseRange'),
    isIterateeCall = require('./_isIterateeCall'),
    toFinite = require('./toFinite');

/**
 * 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 = toFinite(start);
    if (end === undefined) {
      end = start;
      start = 0;
    } else {
      end = toFinite(end);
    }
    step = step === undefined ? (start < end ? 1 : -1) : toFinite(step);
    return baseRange(start, end, step, fromRight);
  };
}

module.exports = createRange;