typescript-accessors.ts

class User {
    private rawUsername: string;

    get userName(): string {
        return "The fullname is: " + this.rawUsername;
    }

    set userName(newName: string) {
        if (newName.length > 10) {
            newName = newName.substr(0, 10);
        }

        this.rawUsername = newName;
    }
}

let e = new User;

e.userName = 'abcdefghijklmnopq';
console.log(e.userName); // abcdefghij