Function: isSubclassOf()

isSubclassOf(value, base): boolean

Tell whether a value is a class (or a constructor function) extending a base class, directly or not. The base class is not its own subclass, and an instance of the subclass is not a subclass. It gives the same result as DTO.isValid(value, DTO.Class(base)), without building a validation schema.

Parameters

value

unknown

The value to test, of any type; a value which is not a function, or a function without prototype (an arrow function), gives false.

base

Function

The base class.

Returns

boolean

true when value extends base, false otherwise.

Throws

When base is not callable or its prototype is not an object (instanceof rejects it), and value is a function with a prototype.

Example

import {isSubclassOf} from 'lakutata/utils'

class Animal {}
class Dog extends Animal {}

console.log(isSubclassOf(Dog, Animal), isSubclassOf(Animal, Animal), isSubclassOf(new Dog(), Animal))
//true false false