/** * Array reduceRight */ function reduceRight(arr, fn, initVal) { // check for args.length since initVal might be "undefined" see #gh-57 var hasInit = arguments.length > 2; if (arr == null || !arr.length) { if (hasInit) { return initVal; } else { throw new Error('reduce of empty array with no initial value'); } } var i = arr.length, result = initVal, value; while (--i >= 0) { // we iterate over sparse items since there is no way to make it // work properly on IE 7-8. see #64 value = arr[i]; if (!hasInit) { result = value; hasInit = true; } else { result = fn(result, value, i, arr); } } return result; } module.exports = reduceRight;