---
id: 587d7dae367417b2b2512b7a
title: Verify an Object's Constructor with instanceof
challengeType: 1
---
## Description
Anytime a constructor function creates a new object, that object is said to be an instance of its constructor. JavaScript gives a convenient way to verify this with the instanceof operator. instanceof allows you to compare an object to a constructor, returning true or false based on whether or not that object was created with the constructor. Here's an example:
```js
let Bird = function(name, color) {
this.name = name;
this.color = color;
this.numLegs = 2;
}
let crow = new Bird("Alexis", "black");
crow instanceof Bird; // => true
```
If an object is created without using a constructor, instanceof will verify that it is not an instance of that constructor:
```js
let canary = {
name: "Mildred",
color: "Yellow",
numLegs: 2
};
canary instanceof Bird; // => false
```
## Instructions
Create a new instance of the House constructor, calling it myHouse and passing a number of bedrooms. Then, use instanceof to verify that it is an instance of House.
## Tests
```yml
tests:
- text: myHouse should have a numBedrooms attribute set to a number.
testString: assert(typeof myHouse.numBedrooms === 'number');
- text: Be sure to verify that myHouse is an instance of House using the instanceof operator.
testString: assert(/myHouse\s*instanceof\s*House/.test(code));
```
## Challenge Seed
```js
/* jshint expr: true */
function House(numBedrooms) {
this.numBedrooms = numBedrooms;
}
// Add your code below this line
```
## Solution
```js
function House(numBedrooms) {
this.numBedrooms = numBedrooms;
}
const myHouse = new House(4);
console.log(myHouse instanceof House);
```