freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/object-oriented-programming/understand-the-constructor-property.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
587d7daf367417b2b2512b7e	Understand the Constructor Property	1	301327	understand-the-constructor-property

--description--

There is a special constructor property located on the object instances duck and beagle that were created in the previous challenges:

let duck = new Bird();
let beagle = new Dog();

console.log(duck.constructor === Bird); 
console.log(beagle.constructor === Dog);

Both of these console.log calls would display true in the console.

Note that the constructor property is a reference to the constructor function that created the instance. The advantage of the constructor property is that it's possible to check for this property to find out what kind of object it is. Here's an example of how this could be used:

function joinBirdFraternity(candidate) {
  if (candidate.constructor === Bird) {
    return true;
  } else {
    return false;
  }
}

Note: Since the constructor property can be overwritten (which will be covered in the next two challenges) it’s generally better to use the instanceof method to check the type of an object.

--instructions--

Write a joinDogFraternity function that takes a candidate parameter and, using the constructor property, return true if the candidate is a Dog, otherwise return false.

--hints--

joinDogFraternity should be defined as a function.

assert(typeof joinDogFraternity === 'function');

joinDogFraternity should return true if candidate is an instance of Dog.

assert(joinDogFraternity(new Dog('')) === true);

joinDogFraternity should use the constructor property.

assert(/\.constructor/.test(code) && !/instanceof/.test(code));

--seed--

--seed-contents--

function Dog(name) {
  this.name = name;
}

// Only change code below this line
function joinDogFraternity(candidate) {

}

--solutions--

function Dog(name) {
  this.name = name;
}
function joinDogFraternity(candidate) {
  return candidate.constructor === Dog;
}