tamda/src/logic/not.ts

Practical functional programming library for TypeScript

import {
  Binary, Denary, Novenary, Nullary, Octonary, Quaternary,
  Quinary, Senary, Septenary, Ternary, Unary,
} from '../operators';

/**
 * Creates a function that negates values returned by a function `fn`.
 * @note Negate means the opposite boolean value, e.g. `negate(true) === false`.
 * @note Ramda's `complement`.
 * @param fn Function to base on.
 */
export function not<T extends Nullary<boolean>>(fn: T): T;
export function not<A, T extends Unary<A, boolean>>(fn: T): T;
export function not<A, B, T extends Binary<A, B, boolean>>(fn: T): T;
export function not<A, B, C, T extends Ternary<A, B, C, boolean>>(fn: T): T;
export function not<A, B, C, D, T extends Quaternary<A, B, C, D, boolean>>(fn: T): T;
export function not<A, B, C, D, E, T extends Quinary<A, B, C, D, E, boolean>>(fn: T): T;
export function not<A, B, C, D, E, F, T extends Senary<A, B, C, D, E, F, boolean>>(fn: T): T;
export function not<A, B, C, D, E, F, G, T extends Septenary<A, B, C, D, E, F, G, boolean>>(fn: T): T;
export function not<A, B, C, D, E, F, G, H, T extends Octonary<A, B, C, D, E, F, G, H, boolean>>(fn: T): T;
export function not<A, B, C, D, E, F, G, H, I, T extends Novenary<A, B, C, D, E, F, G, H, I, boolean>>(fn: T): T;
export function not<A, B, C, D, E, F, G, H, I, J, T extends Denary<A, B, C, D, E, F, G, H, I, J, boolean>>(fn: T): T;

// tslint:disable-next-line: ban-types
export function not(fn: Function): (...args: unknown[]) => boolean {
  // tslint:disable-next-line: only-arrow-functions
  return function() {
    return !fn.apply(undefined, arguments);
  };
}