What is instanceof operator in JavaScript?

The instanceof operator in JavaScript is used to check whether an object is an instance of a specified constructor or class. It returns a boolean value: true if the object is an instance of the specified type or false otherwise. This operator is particularly useful for determining the type of an object at runtime.

Syntax:

object instanceof constructor

Example:


    // Example of using instanceof operator
    function Person(name) {
        this.name = name;
    }
    
    const john = new Person('John Doe');
    
    console.log(john instanceof Person); // Output: true
    console.log(john instanceof Object);  // Output: true
    console.log(john instanceof Array);   // Output: false