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In this video we're going to continue discussing classes in typescript by taking a look at the inheritance

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system.

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So right underneath my class vehicle I'm going to get started by creating a second class definition.

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I'm going to call this thing car like so.

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I want you to think about the relationship between a car and a vehicle in the real world.

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I think that we would say that a car is a type of vehicle and chances are that a whatever a car can

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do a vehicle should be able to do as well.

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So for example a car should be able to drive and it should probably be able to honk as well.

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So we would probably want our class car to have essentially all the same methods or functions of class

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vehicle to make that happen.

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We could either copy paste all these methods down here like so or alternatively we could have our class

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car extend the vehicle class to do so.

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I'm going to find a class car right here and then right after I am say extends Vehicle like so by writing

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in this little additional syntax right here re essentially telling typescript that we wanted to take

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all the different methods inside of this class and essentially copy paste them over to class car.

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Now there's not actually a real copy paste going on here.

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The actual system is a little bit more complicated and we're going to go deeper into that system over

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time.

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But right now we can just imagine that by adding on extends Vehicle we're essentially taking all these

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methods and copy pasting them down like so.

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So now where we create a new vehicle down here rather than creating a vehicle we can delete all that

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and instead let's try creating an instance of a car so I can say const car is new car like so and then

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on this instance of the class we can now call all the different methods that we had associated with

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vehicle so we can say car drive and car Don't honk like so now if I say this file flipped backward my

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terminal and run the file again we're going to see the same output once again when we have a class that

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extends another we can optionally choose to override different methods.

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So for example let's say that we want our car class right here to have a different implementation of

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drive than the parent class to do so we can simply redefine drive inside of car.

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I'm going to again annotate this with the return type of void and maybe inside there for our car rather

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than doing a console log of CHUG CHUG A I instead wanted to do a console log of like vroom like so so

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if we now say this again and flip back over to our terminal we can rerun the file once more and no longer

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are we going to do that chug chug.

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And we'll see vroom instead.

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So we've successfully overridden a method on the child class we refer to talk car as a child class because

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it is extending vehicle we would refer to vehicle in this case as the superclass or the parent class

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all right.

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Now we've taken a look at basic inheritance.

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Let's take another quick pause right here.

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We're going to address a couple more side topics around classes.