AnyFunction type

A type for any function, for generic constraints such as F extends AnyFunction (safer than Function, which also accepts classes and has an untyped call).

import type { AnyFunction } from 'utils';

Signature

export type AnyFunction = (...arguments_: readonly never[]) => unknown;

Example

function once<F extends AnyFunction>(fn: F): F;

Tests

Line coverage: 0 %.

• ✅ accepts functions only

Source

src/types/any-function.ts (on GitHub)

Source code

/**
 * A type for any function, for generic constraints such as `F extends AnyFunction` (safer than `Function`, which also
 * accepts classes and has an untyped call).
 *
 * @example
 * function once<F extends AnyFunction>(fn: F): F;
 */
export type AnyFunction = (...arguments_: readonly never[]) => unknown;

Test file

import type { AnyFunction } from './any-function';

describe('AnyFunction', () => {
  it('accepts functions only', () => {
    expectTypeOf<(a: string) => number>().toExtend<AnyFunction>();
    expectTypeOf<string>().not.toExtend<AnyFunction>();
  });
});

Keywords: any, function, types, type