TypedArray.prototype.reduceRight()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2016.
The reduceRight() method of TypedArray instances applies a function against an accumulator and each value of the typed array (from right-to-left) to reduce it to a single value. This method has the same algorithm as Array.prototype.reduceRight().
Try it
const uint8 = new Uint8Array([10, 20, 30]);
const result = uint8.reduceRight(
(accumulator, currentValue) => `${accumulator}, ${currentValue}`,
);
console.log(result);
// Expected output: "30, 20, 10"
Syntax
reduceRight(callbackFn)
reduceRight(callbackFn, initialValue)
Parameters
callbackFn-
A function to execute for each element in the typed array. Its return value becomes the value of the
accumulatorparameter on the next invocation ofcallbackFn. For the last invocation, the return value becomes the return value ofreduceRight(). The function is called with the following arguments:accumulator-
The value resulting from the previous call to
callbackFn. On the first call, its value isinitialValueif the latter is specified; otherwise its value is the last element of the typed array. currentValue-
The value of the current element. On the first call, its value is the last element if
initialValueis specified; otherwise its value is the second-to-last element. currentIndex-
The index position of
currentValuein the typed array. On the first call, its value isarray.length - 1ifinitialValueis specified, otherwisearray.length - 2. array-
The typed array
reduceRight()was called upon.
initialValueOptional-
Value to use as accumulator to the first call of the
callbackFn. If no initial value is supplied, the last element in the typed array will be used and skipped. CallingreduceRight()on an empty typed array without an initial value creates aTypeError.
Return value
The value that results from the reduction.
Description
See Array.prototype.reduceRight() for more details. This method is not generic and can only be called on typed array instances.
Examples
Sum up all values within an array
const total = new Uint8Array([0, 1, 2, 3]).reduceRight((a, b) => a + b);
// total === 6
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-%typedarray%.prototype.reduceright |