a @pyplane. code Javascript OOPre ) @pyplane_code O1 Introduction In this tutorial we will explore the fundamentals for Object Oriented Programming (OOP) in Javascript in a practical way with examples Table of contents ¢ first class ¢ first instances ¢ inheritance ¢ encapsulation ¢ polymorphism ,° abstract classesé ) @pyplane_code o2 First class On this slide we are creating our first class. Remember to add the constructor method that will enable the creation of instances (objects) based on our class class Animal { constructor(name, age) { faecal eT Dp CmE-\+( Ea bd (otra mene iad “The name of the animal is ${this.name} and age is ${this.age}* ) i6 ) @pyplane_code ‘o}c} First instances On the previous slide we created anew class, addeda constructor method that takes in 2 arguments - name and age. To create an object from this constructor method we need to use the new keyword and pass in the given name and age of the animal object that we are creating. We also have added a getInfo method that returns the information about the object eo tam eee te et LOM VP TG > ae) console. log(firstAnimal) console. log(firstAnimal.getInfo()) const secondAnimal = new Animal('Barney', 5) console. log(secondAnimal) console. log(secondAnimal.getInfo()) PU Me Hoe Ce ee Ra a TM EMT SD The name of the animal is Barney and age is 5(6 ) @pyplane_code (ey! nati t-te C9 TS Mantel c= pre Ve L aU Mgr] -U-)>) (Xe | ga =X OR oh 1 Cy all the methods and properties of another one (parent class) and makes it possible to extend the parent class by adding more BCS a cou iane Coe aac eT a se Breau) Bere a) o Tren cea H + eee lacie iet Cees SCL nS Brean uae Pent aes st ba rey an acre eeU ) console. Log(myDog. get Info()) UCR Nr a) ee Tem Ciao} Ca eee Gee Tce console. log(myCat.getInfo()) ComeMel oien sta) i ee a eee ed Ce) Cres The name of the animal is Whiskers and age is 5 ca@ ) @pyplane_code @) 5 Encapsulation Encapsulation is arestrictionmechanism making accessing the data impossible without using special methods dedicated for this. In the example below we marked weight as a private property and in order to get and set a value we need to use the getter and setter method Germ Tat cue Ur Lane #weight; ——»_ mark as private constructor(name, age, weight) { super(name, age) this.#weight = weight } PiaasCO mee ———— getter fete gee Sete } setWeight(weight) {——»__.- sett ter eC em hd V ¥ Output: eee Nec amet meh Ol Fel te PT console. log(myCat.getWeight()) 5kg myCat. setWeight('6kg') ie eee eben lads Kel OD)é ) @pyplane_code 06 Polymorphism Polymorphism is a concept that utilizes inheritance for reusing methods multiple times with a different behaviour depending on class types. To understand this lets look at our example - in the dog class we will remove the bark method andin the animal class we'lladda makeSound method which will be overridden by cat and dog classes ere Urea class Cat extends Animal { Erasce tr ae ont Coa Le msc a ne Cee eat Era CS) ES ey Pret aene tg } } cco a makeSound() { Eee oT i] + + 2 } COSC ean (ae a Cae ae a Oe 1 ee oe PL ECD Roc ear an Seatac a ee Ee ECCT OPEL LCs OD) Ree ec) CIC Cera Lora) makeSound() { oa } i output: woof meowee rey, Abstract class p1 Abstract class is a class which can't be instantiated and require subclasses which inherit from a particular abstract class to provide implementations. We will change the Animal class to an abstract class. It will not be possible to create ainstance of this class anymore like on slide number 3 and we will mark makeSound as an abstract method -in order to use it, asubclass must declare its own implementation of this method class Animal { aaa eT oe 8 ea this.age = age; pRICPeR edie UPC LO ne throw new Error("Can't create a instance of Abstract class"); } b LLC LC LS SNe ee Coe eet SC esé ) @pyplane_code os Abstract class p2 EER fmre uC UF L Mee fe aaa acl Pee |+ Pe a De ETI) BP aa gl LLL O mane cad class Cat extends Animal { fl aaa ate G LL eee|: eee Tea T+ 0 this.weight = weight TES LO ih CA Led THE 3s Y can't // const myAnimal = new Animal('Barney', 3) ——» instantiate const myDog = new Dog('Rex', 2, ‘German Sh.') anymore const myCat = new Cat('Whiskers', 5, '5kg') this will give us an error since CLE Meche LC Oa cactoltiatel Maite elel ane cel eel aDid you learn something? Don't forget to save this post and drop alike Follow me for much more stuff like this :) wu a soli ole clot ed Lv | Like Save for later i