JavaScript Classes #4: Inheritance & Extends - JavaScript OOP Tutorial

By using the "extends" keyword with your JavaScript classes you are able to create inheritance which is where you have a child class that inherits the instance properties and methods of its parent class.

You'd typically use a feature like this on the server-side with NodeJS as this can be considered to be a complex design - although classes can be used to represent similar visual components on the front-end.

In this video I take you through a simple example of how you can make use of the extends keyword to achieve inheritance - you'll see how we create a "child" version of a Person class, a Programmer. programmer has all the features of a person but with a little but extra!

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[ymarchitect]

Your way not to hide occasional typing mistakes and executin errors is the better teaching method than showing perfect procedures. I like the way.

[YoungmeePark]

Always. Simple clear. Love your teachings

[erickoavenada]

Great explanations, from the start i understand what i didnt understood before

[kiritosenpai]

mesmo sem entender o que ele estava dizendo, suas separações e jeito de fazer me deram uma luz, obrigado!!!

[LetsGeTDeep]

Hiya mate, don't mind me just saying how much I love this series again lol

[HumAnTargt]

thanks, was really confused about the super method, think i got it now!

[dopetag]

Wow! Amazing explanation and examples. Thank you!

[mekanarazmedov]

Great explanation, thank for this video.

[ygge]

Hi Dom, thank you for this tutorial. I'm wondering if "extends" is somehow similar to Object.prototype?

[zsofiaszabo]

Thank you, it was a really helpful video! :)

[cannabisanomaly]

Thank you very much for the informative video! You have a knack for teaching. I had one question though; when you form the class's instance properties:

class Person {
constructor(_name, _age) {
this.name = _name;
this.age = _age;
}

Would the correct syntax to indicate a private property be this instead?

class Person {
constructor(name, age) {
this._name = name;
this._age = age;
}

Since that way, once the actual object instance is seen with the property name, it becomes more apparent that it's a private property?

Really small detail, but just wasn't sure what the so-called "standard" should be. Thank you again for a great video!

[yamacode]

Does super(_name, _age) being the name and age properties to the new child class. Am I right in my understanding that once you have used super(_name, _age) you save time by not writing those properties yourself and just "extend" it from another class?. If the parent class does not have a property you need, you can add it yourself like you did with yearsOfExperience.

[yamacode]

I also have other question, sorry for taking your time. The only way to access the property or method of a child class is by using its own name and not its parents. Is this correct?

[VishnuSunilkumar]

I love your wpm. Loved listening to your keys.

BTW Thanks for making this video.

[mdabdullah-dgxs]

I also have another question for you, sorry for taking your time. can we inherit multiple parent classes in our one child class?
If it can be done, how do I do it?

[yamacode]

I dont understand this too
const programmers = [
new Programmer("Dom", 54, 12),
new Programmer('Jeff', 24, 4)

] I know its an array but how do you call a class from inside an array, how does this code work?

[akbarangkasa]

when you realise a 10 minutes youtube video nowadays worth more than a whole semester of your college smh.. 😤

[contactmerrou]

Nice video, thanks! Though, please use some girls' names for your examples. Not only men code ;)