Interface inheriting Type script - oop

Question

I just want to write a User module which has multiple classes i.e. UserDetail,UserResestPassword so on .
There are some common properties which these classes are going to share , one approach I can declare property on every class and Initialize it.
The second approach is I will use of inheritance this will need to declare in
interface
export interface Iuser {
UserID:string;
UserName:string
}
and implement it into classes
import {Iuser} from './IuserDetail'
class UserInfo implements Iuser {}
My question is, is't supported in typescript? if not what are the way around to sort out this

Answer 1

In TypeScript there is a feature called "type erasure" where all of the type information is removed during compilation so the JavaScript output contains no type annotations, interfaces, or ambient declarations - only real code.
This means that when you ask your module loader (at runtime) to get you the Iuser interface, it doesn't exist in the JavaScript file.
My recommendation would probably be to put your interfaces in files with their primary implementation. That means you don't end up attempting to load a module that is just a blank file.
For example:
export interface Iuser {
UserID:string;
USerName:string
}
export class UserInfo implements Iuser {
}
And in other files you can:
import * as User from './UserInfo'
export class Example implements User.Iuser {
}

Answer 2

Look at this example:
Interfaces don't actually exist after compilation but are strictly used for type checking.
// i-user.ts
export interface IUser {
UserID:string;
UserName:string
}
Just like interfaces in other languages you have to implement all members of an interface. TypeScript will check if you are missing any.
// user-info.ts
import { IUser } from './i-user'
export class UserInfo implements IUser {
UserID:string;
UserName:string;
OtherInfo:string;
}
Using extend all parent methods will be available and you don't need to implement them again.
// specific-user-info.ts
import { UserInfo } from './user-info'
class SpecificUserInfo extends UserInfo {
logInfo() {
console.log(this.UserID, this.UserName);
}
}