W3Schools Tryit Editor

// @ts-check

class ValidationError extends Error {
  /** @type {string | undefined} */
  field;
  /**
   * @param {string} message
   * @param {string=} field
   */
  constructor(message, field) {
    super(message);
    this.name = 'ValidationError';
    this.field = field;
    Object.setPrototypeOf(this, ValidationError.prototype);
  }
}

class DatabaseError extends Error {
  /** @type {number} */
  code;
  /**
   * @param {string} message
   * @param {number} code
   */
  constructor(message, code) {
    super(message);
    this.name = 'DatabaseError';
    this.code = code;
    Object.setPrototypeOf(this, DatabaseError.prototype);
  }
}

/** @param {{name?: string, email?: string}} user */
function validateUser(user) {
  if (!user.name) {
    throw new ValidationError('Name is required', 'name');
  }
  if (!user.email || !user.email.includes('@')) {
    throw new ValidationError('Invalid email format', 'email');
  }
}

try {
  validateUser({ email: 'no-at-symbol' });
} catch (error) {
  if (error instanceof ValidationError) {
    console.log(`Validation error in ${error.field}: ${error.message}`);
  }
}

try {
  validateUser({ name: 'Alice', email: 'not-an-email' });
} catch (error) {
  if (error instanceof ValidationError) {
    console.log(`Validation error in ${error.field}: ${error.message}`);
  }
}