instance of in JS code example

Example 1: instanceof javascript

var color = "red";
var color2 = {};
color instanceof String // will return true
color2 instanceof Object // will return true

Example 2: js class check if new instance

new Date() instanceof Date;  // => true

Example 3: insanceof

The instanceof operator tests to see if the prototype property of a constructor 
appears anywhere in the prototype chain of an object. The return value is a 
boolean value.
For example :-

function Car(make, model, year) {
  this.make = make;
  this.model = model;
  this.year = year;
}
const auto = new Car('Honda', 'Accord', 1998);

console.log(auto instanceof Car);
// expected output: true

console.log(auto instanceof Object);
// expected output: true