isPrototypeOf < Object < JavaScript

The isPrototypeOf() method of Object instances checks if this object exists in another object's prototype chain.

    
    function Foo() {}
    function Bar() {}

    Bar.prototype = Object.create(Foo.prototype);

    const bar = new Bar();

    console.log(Foo.prototype.isPrototypeOf(bar));
    // true

    console.log(Bar.prototype.isPrototypeOf(bar));
    // true