Enumerable.prototype.reduce - proc documentation

method Enumerable.prototype.reduce



Enumerable.prototype.reduce(reduceFn: (acc: T,
item: T,
index: number,
) => T | Promise<T>): Promise<T>

Reduce the sequence to a single value.

Executes a reducer function on each element, passing the accumulated result from one element to the next.

Examples

import { range } from "jsr:@j50n/proc";

const sum = await range({ from: 1, until: 5 })
  .reduce((acc, n) => acc + n, 0);
// 15



reduceFn: (acc: T,
item: T,
index: number,
) => T | Promise<T>

The reducer function.

Promise<T>

The final accumulated value.

TypeError if the iteration is empty and no initial value provided.



Enumerable.prototype.reduce<U>(reduceFn: (acc: U,
item: T,
index: number,
) => U | Promise<U>,
zero: U,
): Promise<U>

Reduce the sequence to a single value with an initial value.



reduceFn: (acc: U,
item: T,
index: number,
) => U | Promise<U>

The reducer function.



zero: U

The initial accumulator value.

Promise<U>

The final accumulated value.