reduceRight()

Apply a reducer Function to each array element, from right to left, to get a single value.

Signature

reduceRight(reducer: (acc: Any, val: Any) => Any): Any

Description

The reduceRight() method applies a reducer Function to each Array element, from right to left, by passing the reducer value returned from the previous iteration and the next Array element as parameters.The result of the last calculation is the value returned by the method.

The calling Array isn’t changed.

Parameters

Parameter Type Required Description

reducer

Function

Yes

Function to invoke for each element of the calling Array.

reducer parameters:

Parameter Type Required Description

acc

Any

Value returned by the previous invocation of reducer.

val

Any

Yes

Current Array element to be evaluated.

Return value

Type Description

Any

Result of the last reducer calculation.

Examples

Reduce the Array elements, right to left:

["A", "B", "C"].reduceRight((prev, cur) => prev + cur)
"CBA"

This shows the steps of each iteration of the reducer Function:

Reducer call Accumulator value Current value Array index Result

First call

""

"C"

2

"C"

Second call

"C"

"B"

1

"CB"

Third call

"CB"

"A"

0

"CBA"

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