Private properties and methods in JavaScript

Published August 6, 2020

Private properties and methods are those which can be accessed only in the class.

These properties and methods are not inherited.

To make a property or a method in a class private, you need to use the # symbol before the property name or method name.

⚠️ NOTE: Private property and methods is a new addition to JavaScript. Use with caution.

class User {
  // private property
  #category = "User";

  // public property
  isAlive = true;

  // private method
  #checkUserAlive() {
    return isAlive;
  }
}

Here you can see that we added a special symbol # to the property category and method checkUserAlive() method.

Now if you try to access the private property or method outside the class it will throw an error.

class User {
  // private property
  #category = "User";

  // public property
  isAlive = true;

  // private method
  #checkUserAlive() {
    return isAlive;
  }
}

// create a object
const john = new User();

// try to access private property category
console.log(john.#category); // error

// try to call checkUserAlive() private method
console.log(john.#checkUserAlive()); // error

You can only use the private properties and methods for usage within the class only.

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