Difference between interfaces and classes in TypeScript

In this article, we will see what is the Difference between "interface" and "Classes" in TypeScript.

Interface: Interface is the virtual structure that is used for type-checking. In TypeScript we use interface keyword to create the new interface with identity. It create the structure for the same datatype. Interface is the structure which define the properties and method for object with name and type.

Syntax:

interface New_Interface{ // This is interface Body }

Features:

• It has loose coupling.
• It supports multiple Inheritance.

Example 1:

// Interface for Class
interface ForClass {
    readonly var1:string;               
}

let newclass: ForClass = {var1:"Interface"};
console.log(newclass);

Output:

{ var1: 'Interface' }

Example 2:

// Interface for Object with extends function 
interface ForObj {
    First: string
}

interface forNewObj extends ForObj {
    Second: number
}

let newArray: forNewObj = {
    First: "Interface for Object",
    Second: 2
};

console.log(newArray);

Output:

{ First: 'Interface for Object', Second: 2 }

Classes: They are the skeleton of objects with its use we implement objects. In TypeScript, we use class Keyword to create the constructor for the object. It can have properties, methods and variables.

Syntax:

class geeks {
    // Class property and methods
    // are created here
}

Features:

• In classes it support member visibility.
• It supports member overriding.
• it supports inheritance.

Example:

class Geeks {      
    name : string ;
    articles: number ; 
    cp_problems: number;

    // Constructor of class
    constructor(name:string, articles: number, cp_problems: number) {
        this.name = name;
        this.articles = articles;
        this.cp_problems = cp_problems;
    }
                 
    // About object 
    About() : void {
        console.log("Name of Geeks: " + this.name );
        console.log("No. of articles by Geeks: "
            + this.articles);
        console.log("No. of cp problems sol by Geeks: "
            + this.cp_problems)
    }
}
var geek1 = new Geeks("Abhinav", 87, 560);
geek1.About();

Output:

Name of Geeks: Abhinav
No. of articles by Geeks: 87
No. of cp problems sol by Geeks: 560

The difference between interface and classes are below: