Instance Validation

class CheckingAccount{
    _clientId;
    _email;
    _firstName;
    _lastName;

    constructor(clientId, email, firstName, lastName){
        this.clientId = clientId;
        this.email = email;
        this.firstName = firstName;
        this.lastName = lastName;
    }
    get clientId(){
        return this._clientId;
    }
    set clientId(value){
       if(value.length !== 6){
        throw new TypeError('Client ID must be a 6-digit number');
       }
       this._clientId = value;
    }

    get firstName(){
        return this._firstName;
    }

    set firstName(value){
        this.nameValidation(value,'First');
        this._firstName = value;
    }

    get lastName(){
        return this._lastName;
    }

    set lastName(value){
        this.nameValidation(value, 'Last');
        this._lastName = value;
    }

    nameValidation(value, prop){
        if(value.length < 3 || value.length > 20){
            throw new TypeError(`${prop} name must be between 3 and 20 characters long`);
        }
       const pattern = /^[A-Za-z]+$/g;
       if(!pattern.test(value)){
        throw new TypeError(`${prop} name must contain only Latin characters`);
       }
    }
}
let acc = new CheckingAccount('1314', 'ivan@some.com', 'Ivan', 'Petrov');