How to fix Property 'x' is private and only accessible within class 'Y' in TypeScript

// BEFORE: Error TS2341
class User {
  private email: string;

  constructor(email: string) {
    this.email = email;
  }
}

const user = new User("[email protected]");
console.log(user.email); // Error: Property 'email' is private

// AFTER: Make it public
class User {
  public email: string; // or just: email: string;

  constructor(email: string) {
    this.email = email;
  }
}

const user = new User("[email protected]");
console.log(user.email); // OK: "[email protected]"

// BEFORE: Error in subclass
class Animal {
  private name: string;

  constructor(name: string) {
    this.name = name;
  }
}

class Dog extends Animal {
  bark() {
    console.log(`${this.name} barks!`); // Error: 'name' is private
  }
}

// AFTER: Use protected
class Animal {
  protected name: string;

  constructor(name: string) {
    this.name = name;
  }
}

class Dog extends Animal {
  bark() {
    console.log(`${this.name} barks!`); // OK: protected allows subclass access
  }
}

const dog = new Dog("Rex");
dog.bark(); // OK: "Rex barks!"
console.log(dog.name); // Still Error: protected is not externally accessible

class BankAccount {
  private balance: number;

  constructor(initialBalance: number) {
    this.balance = initialBalance;
  }

  // Public getter method
  getBalance(): number {
    return this.balance;
  }

  // Public method to modify balance (controlled)
  deposit(amount: number): void {
    if (amount > 0) {
      this.balance += amount;
    }
  }
}

const account = new BankAccount(1000);
console.log(account.balance); // Error: balance is private
console.log(account.getBalance()); // OK: 1000
account.deposit(500);
console.log(account.getBalance()); // OK: 1500

class User {
  private _email: string;

  constructor(email: string) {
    this._email = email;
  }

  // Getter accessor
  get email(): string {
    return this._email;
  }

  // Setter accessor with validation
  set email(value: string) {
    if (!value.includes("@")) {
      throw new Error("Invalid email format");
    }
    this._email = value;
  }
}

const user = new User("[email protected]");
console.log(user.email); // OK: "[email protected]" (calls getter)
user.email = "[email protected]"; // OK: sets via setter
user.email = "invalid"; // Throws error: Invalid email format
console.log(user._email); // Error: _email is private

class Timer {
  private startTime: number;

  constructor() {
    this.startTime = Date.now();
  }

  // Public method that uses private property internally
  getElapsedSeconds(): number {
    return (Date.now() - this.startTime) / 1000;
  }

  reset(): void {
    this.startTime = Date.now();
  }
}

const timer = new Timer();
console.log(timer.startTime); // Error: startTime is private
console.log(timer.getElapsedSeconds()); // OK: 0.123
timer.reset(); // OK: resets internal startTime

class SecureData {
  #apiKey: string; // JavaScript private field

  constructor(key: string) {
    this.#apiKey = key;
  }

  validateKey(input: string): boolean {
    return input === this.#apiKey;
  }
}

const data = new SecureData("secret-123");
console.log(data.#apiKey); // Error at compile-time AND runtime
console.log((data as any).#apiKey); // Still error at runtime
console.log(data.validateKey("secret-123")); // OK: true