Now set up the prototype chain for the Teacher prototype to inherit from the Person prototype

Question

This is pretty much one of the difficult course I have ever taken on JavaScript. From the start to the end is all confusing to me. I have no clue what I am even doing or what the challenge is asking. I can't do the challenge if I don't understand what is goind on. I need to do some research on this JavaScript Object Oriented programming or read a book on it.
```person.js
function Person(firstName, lastName) {
  this.firstName = firstName;
  this.lastName = lastName;
}
Person.prototype.fullName = function() {
 return this.firstName + " " + this.lastName; 
};
```
```teacher.js
function Teacher(firstName, lastName, roomNumber) {
   Person.call(this,firstName,lastName)
  this.room = roomNumber; 
}
Teacher.prototype = Object.create(person.prototype)
```

rydavim · Answer

Disclaimer: I'm not an expert on this topic (I'm taking this course right now), but I'll do my best.
For the first part of the challenge, you're using call() to chain constructors that share common attributes. Because a Teacher is very similar to a Person, you can use Person to help shorten the Teacher constructor.
javascript
function Teacher(firstName, lastName, roomNumber) {
  Person.call(this, firstName, lastName);
  // this.firstName = firstName;  // You don't need these lines anymore.
  // this.lastName = lastName;  // The Person call is doing this for you.
  this.room = roomNumber;
}

In this example, it's not that big a change. But you can call the Person constructor on lots of kinds of people, assuming you had constructors for them. What if you had Teachers, Students, Staff, Mods, ect. It would be convenient to reuse the Person call for all of them, yeah?
Edit - Added the second part of the challenge.
For the second part of the challenge, you're setting Teacher's prototype to Person's constructor, meaning you inherit all of Person.prototype's properties and methods.
javascript
Teacher.prototype = Object.create(Person.prototype);

Abe Layee · Answer

Thank you @rydavim (https://teamtreehouse.com/rydavim). I was just reading JavaScript OOP on that website you showed .

Abe Layee · Answer

so what  about the second part of the challenge. I have no idea what to do.
```JavaScript
function Teacher(firstName, lastName, roomNumber) {
   Person.call(this,firstName,lastName)
  this.room = roomNumber; 
}
Teacher.prototype = Object.create(person.prototype)
```

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Now set up the prototype chain for the Teacher prototype to inherit from the Person prototype

3 Answers

rydavim

rydavim

Abe Layee

Abe Layee

rydavim

rydavim

Abe Layee

Abe Layee