function

@nick/is/function

isFunction

Signature

function isFunction<T extends FunctionOrConstructor>(
  it: T | unknowns,
): it is FunctionOrConstructor<any, any, any> extends T ? Function : T;

Check if the given value is a function.

Parameters

Name	Info
it	The value to check.

Returns

true if the value is a function, false otherwise.

Category

Standard

Examples

import { isFunction } from "jsr:@nick/is/function";

console.log(isFunction(() => {})); // true
console.log(isFunction(function () {})); // true
console.log(isFunction(class {})); // true
console.log(isFunction(new Function())); // true
console.log(isFunction({})); // false
console.log(isFunction(1)); // false

isFunction

Signature

function isFunction<T = any, A extends readonly any[] = any[]>(
  it: Fn<T, A> | unknowns,
): it is Fn<T, A>;

isFunction

Signature

function isFunction<T = any, A extends readonly any[] = any[], R = any>(
  it: ThisFn<T, A, R> | unknowns,
): it is ThisFn<T, A, R>;

isFunction

Signature

function isFunction(it: unknown): it is Function;

isFunction

Signature

function isFunction(it: unknown): it is FunctionOrConstructor;

Fn

Signature

export type Fn<T = any, A extends readonly any[] = any[]> = (...args: A) => T;

Type Parameters

• T (default: any)
• A extends readonly any[] (default: any[])

---

FunctionOrConstructor

Signature

export type FunctionOrConstructor<
  T = any,
  A extends readonly any[] = any[],
  R = void,
> = Constructor<R, A> | Fn<R, A> | ThisFn<T, A, R> | Function;

Type Parameters

• T (default: any)
• A extends readonly any[] (default: any[])
• R (default: void)

---

ThisFn

Signature

export type ThisFn<T = any, A extends readonly any[] = any[], R = any> = (
  this: T,
  ...args: A
) => R;

Type Parameters

• T (default: any)
• A extends readonly any[] (default: any[])
• R (default: any)

---