understanding interface in typescript

1. interface is one of most important part of typescript they contain  properties function or event but only definition.



work code example->https://stackblitz.com/edit/typescript-gzh1np

example of interface is=>

//understanding interface in typescript

//a interface can be used liked a object in js

//for example

interface user

{

//string typer property

name:string,

//number type property

age:number

//string type property

occupation:string;

//height can be string or number :)

height:string|number

}

//create a instance of user

var manish:user={

name:"manish chauhan",

age:27,

occupation:"game developer",

height:30

}

//access a property

console.log(manish.name);

//example2------------------------------------------------>>

//interface can be nested for example suppose for example

//suppose a group of student from different class

interface student

{

studentName:string,

studentAge:number,

//student class can be string or number

studentClass:string|number,

//and optional parameter declare in a interface like below

dressCode?:string

}

//now student group which contain differnt class student

interface group

{

groupName:string,

group:student[]

}

//now there can a serval group inside one school so we create one more interface which contain holds all groups of one school

interface school

{

schoolName:string,

groups:group[];

}

//now solve this problem using nested interface

var myschool:school={

schoolName:"apj schoool",

groups:[

//first group

{

groupName:"apple group",

group:[

{

studentName:"manish rawat",

studentAge:18,

studentClass:"12"

} ,

{

studentName:"seema",

studentAge:18,

studentClass:"11"

},

{

studentName:"rahul",

studentAge:17,

studentClass:"11"

}

]

},

{

groupName:"mango group",

group:[

{

studentName:"jeet",

studentAge:18,

studentClass:"12"

} ,

{

studentName:"reena",

studentAge:18,

studentClass:"11"

},

{

studentName:"monu",

studentAge:17,

studentClass:"11"

}

]

}

]

}

//access any student

const student=myschool.groups[0].group[0];

console.log(student.studentName);

//access all student

//loop each group

myschool.groups.forEach((value,index)=>

{

//loop each group

value.group.forEach((subvalue,subindex)=>

{

//get each student value from each group

console.log(subvalue);

}

)

}

)

//using interface as a part of a class we can define all required function for a class

//class--------------------------

interface userInterFace

{

login(userName:string,password:student),

register(userName:string,password:student),

update(userId:number),

delete(userId:number)

}

class NewUser implements userInterFace

{

constructor()

{

}

login(userName:string,password:student)

{

}

register(userName:string,password:student)

{

}

update(userId:number)

{

}

delete(userId:number)

{

}

}

var x=new NewUser();

//x.update(2);