froebel/unary.d.ts

TypeScript utility library

import { Take_, λ } from "./types";
/**
 * Turns `fun` into a unary function (a function that only accepts one
 * argument).
 *
 * Note: `fun` must accept at least one argument and must not require more than
 * one argument.
 *
 * @example
 * ```
 * ['1', '2', '3'].map(unary(parseInt))  // -> [1, 2, 3]
 * ```
 */
declare const unary: <T extends λ<[any], any>>(fun: Parameters<T> extends [] ? never : T) => Unary<T>;
export default unary;
declare type Unary<T extends λ<[any]>> = λ<Take_<Parameters<T>, 1>, ReturnType<T>>;