froebel/unzip.d.ts

TypeScript utility library

import type { λ } from "./types";
declare type Unzip<T extends unknown[]> = {
    [I in keyof T]: T[I][];
};
/**
 * Reverse of {@link zip}. Takes a list of tuples and deconstructs them into
 * an array (of length of the tuples length) of lists each containing all the
 * elements in all tuples at the lists index.
 *
 * @example
 * const [nums, chars] = unzip([1,'a'], [2,'b'], [3,'c'])
 * console.log(nums)  // prints: [1, 2, 3]
 * console.log(chars) // prints: ['a','b','c']
 */
declare const unzip: <T extends unknown[]>(...zipped: [...T][]) => Unzip<T>;
export default unzip;
/**
 * Same as {@link unzip} but accepts an `unzipper` function for each tuple
 * index. The `unzipper`'s return value is used as the value in the list at
 * that index returned from `unzipWith`.
 *
 * The `unzipper` takes the current element as its first argument, an
 * accumulator as second argument (initially `undefined`) and its return value
 * is the accumulator passed into the next invocation.
 *
 * @example
 * const [nums, str] = unzipWith(
 *   [ [1,'a'], [2,'b'], [3,'c'] ],
 *   (n, acc: number[] = []) => [...acc, n],
 *   (c, str = '') => str + c
 * )
 *
 * console.log(nums) // prints: [1, 2, 3]
 * console.log(str)  // prints: 'abc'
 */
export declare const unzipWith: <T extends unknown[], U extends { [I in keyof T]: λ<[cur: T[I], acc: any], any>; }>(zipped: [...T][], ...unzippers: U) => { [I_1 in keyof U]: ReturnType<U[I_1]>; };