constructor overload in TypeScript

constructor-overload.ts

class User {

    public name: string;
    public age: number;
    public languages: string[];

    constructor(name:string);
    constructor(name:string, age?: number);
    constructor(name:string, age: number, languages?: string[])
    constructor(name?:string, age?: number, languages?: string[]) {
        Object.assign(this, {name, age, languages});
    }
}

let u1 = new User('bob');
let u2 = new User('thomas', 20);
let u3 = new User('jack', 25, ['en', 'jp']);

console.log(u1); // User { name: 'bob', age: undefined, languages: undefined }
console.log(u2); // User { name: 'thomas', age: 20, languages: undefined }
console.log(u3); // User { name: 'jack', age: 25, languages: [ 'en', 'jp' ] }