constructor

@nick/is/constructor

isConstructor

Signature

function isConstructor<T>(it: unknown): it is Constructor<T>;

Checks whether a given value is a constructor function.

In this context, a constructor is defined as a function with a prototype own property that contains an object with an own constructor property that points back to the constructor function itself.

Parameters

Name	Info
it	The value to check.

Returns

true if the value is a constructor function; otherwise, false.

Category

Guards

Examples

import { isConstructor } from "jsr:@nick/is/constructor";

class Foo {}
console.log(isConstructor(Foo)); // true
console.log(isConstructor(Foo.prototype.constructor)); // true
console.log(isConstructor(class {})); // true
console.log(isConstructor(function () {})); // true

console.log(isConstructor({})); // false
console.log(isConstructor(null)); // false
console.log(isConstructor(Foo.prototype)); // false
console.log(isConstructor(() => new Foo())); // false

Constructor

Represents a constructor function that creates instances of type T.

Category

Types

Type Parameters

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

---

Properties

prototype

readonly prototype: Prototype<T, this>;

---