reduceRight.js
926 Bytes
/**
* 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;