JavaScript Inheritance

JavaScript does not have classes unlike other languages. It uses the concept of prototypes and prototype chaining for inheritance.

Let’s implement prototype chaining

//SuperType constructor function

function SuperType(){

    this.name = "Virat"

   }

   

   //SuperType prototype

   SuperType.prototype.getSuperName = function(){

    return this.name

   }

   

   //SubType prototype function

   function SubType(){

    this.age = 26

   }

   

   //Inherit the properties from SuperType

   SubType.prototype = new SuperType();

   

   //Add new property to SubType prototype

   SubType.prototype.getSubAge = function(){

    return this.age;

   }

   

   //Create a SubType object

   var subTypeObj = new SubType();

   console.log(subTypeObj.name); //Output: Virat

   console.log(subTypeObj.age); //Output: 26

   console.log(subTypeObj.getSuperName()); //Output: Virat

   console.log(subTypeObj.getSubAge()); //Output: 26

Above code defines two consructor functions, SuperType and SubType. By default, SubType.prototype has a constructorfunction which points to the constructor function itself and proto property which inherits the default object properties.

//Inherit the properties from SuperType
SubType.prototype = new SuperType();

Now, SubType function has access to all the SuperType properties and methods.

Reference; https://hackernoon.com/