What's the output?

Question

```javascript
function Person(firstName, lastName) {
  this.firstName = firstName;
  this.lastName = lastName;
}

const member = new Person('Lydia', 'Hallie');
Person.getFullName = function() {
  return `${this.firstName} ${this.lastName}`;
};

console.log(member.getFullName());
```

Accepted Answer

In JavaScript, functions are objects, and therefore, the method `getFullName` gets added to the constructor function object itself. For that reason, we can call `Person.getFullName()`, but `member.getFullName` throws a `TypeError`.

If you want a method to be available to all object instances, you have to add it to the prototype property:

```js
Person.prototype.getFullName = function() {
  return `${this.firstName} ${this.lastName}`;
};
```

Related Concepts

What's the output?

All object have prototypes.

What's the output?

Related Concepts

Related Concepts

What's the output?

All object have prototypes.

What's the output?

Related Concepts