@applicaster/zapp-react-native-utils/utils/mapAccum.ts

Applicaster Zapp React Native utilities package

import { curry } from "lodash";

/**
 * A native reimplementation of Ramda's mapAccum.
 *
 * @template A, B, C
 * @param {(acc: A, value: B) => [A, C]} fn - Function returning [newAcc, mappedValue]
 * @param {A} acc - Initial accumulator
 * @param {B[]} list - List to process
 * @returns {[A, C[]]} - Tuple of [final accumulator, mapped array]
 */
export const mapAccum = curry((fn, acc, list) => {
  const result = [];
  let currentAcc = acc;

  for (let i = 0; i < list.length; i++) {
    const [nextAcc, mapped] = fn(currentAcc, list[i]);
    currentAcc = nextAcc;
    result.push(mapped);
  }

  return [currentAcc, result];
});