In TypeScript, access modifiers—public, private, and protected—are used to control the visibility and accessibility of class members (properties and methods) within a class and its subclasses. They play a crucial role in enforcing encapsulation and managing the access to class members. Let's delve deeper into these access modifiers:

public:

• Default Modifier: If no access modifier is specified, members are considered public by default.

• Accessible Everywhere: public members are accessible from inside the class, from instances of the class, and even from external sources.

Example:

javascriptclass Car {
  public make: string;
  public model: string;

  constructor(make: string, model: string) {
    this.make = make;
    this.model = model;
  }

  public getInfo(): string {
    return `Make: ${this.make}, Model: ${this.model}`;
  }
}

private:

• Restricted Access: private members are only accessible within the class they are declared in.

• Inaccessible from Outside: They cannot be accessed from outside the class or from instances of the class.

Example:

javascriptclass BankAccount {
  private balance: number;

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

  private deduct(amount: number) {
    this.balance -= amount;
  }
}

protected:

• Accessible in Subclasses: protected members are accessible within the class they are declared in and its subclasses (classes that inherit from it).

• Not Accessible from Instances: They cannot be accessed from instances of the class directly.

Example:

javascriptclass Animal {
  protected sound: string;

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

class Dog extends Animal {
  makeSound() {
    console.log(`The dog makes a ${this.sound} sound.`);
  }
}

Key Points:

• Access modifiers enforce encapsulation and control the visibility of class members.

• public members allow broad access, private restricts access to the defining class only, and protected allows access within inheriting classes.

• TypeScript's compiler enforces these access controls at compile-time, contributing to code reliability and maintainability.

Use Cases:

• public is commonly used for members meant to be accessible from outside the class.

• private is useful for sensitive data or implementation details that should not be exposed outside the class.

• protected is employed when a class's property or method needs to be accessed by subclasses.

Understanding and using access modifiers in TypeScript is fundamental for writing maintainable and secure object-oriented code, ensuring proper encapsulation and controlling the accessibility of class members based on specific design considerations.