TypeScript Tutorial in Hindi #33 keyOf Operator

keyOf in TypeScript

What is keyof?

Example

How to use object keys with keyof

Interview Questions

The keyof keyword in TypeScript is used to

get the keys of a type

as a union of string.

It is primarily used for type safety when working with objects.

keyOf.ts

type PersonT={

name:string,

age:number,

isEmp:boolean

}

let PersonData:PersonT={

name:'Anil sidhu',

age:30,

isEmp:true

}

type PersonX=keyof PersonT;

// let PersonDataX:PersonX;

let PersonDataX:keyof PersonT;;

PersonDataX="name";

PersonDataX="age";

PersonDataX="isEmp";

let UserX:keyof typeof PersonData="name"

keyOf.js

"use strict";

let PersonData = {

name: 'Anil sidhu',

age: 30,

isEmp: true

};

// let PersonDataX:PersonX;

let PersonDataX;

;

PersonDataX = "name";

PersonDataX = "age";

PersonDataX = "isEmp";

let UserX = "name";