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Getters and Setters

In JavaScript, we can use getters and setters to control access to an object's properties.

Getters

A getter is a method that gets the value of a specific property.

const person = {
  firstName: 'John',
  lastName: 'Doe',
  get fullName() {
    return this.firstName + ' ' + this.lastName;
  }
};

console.log(person.fullName); // John Doe

In the example above, we have a person object with a fullName getter. When we call person.fullName, the get method is executed and returns the value of firstName and lastName. The get method is called without using parentheses. It looks like we are accessing a property, but in reality, we are calling a method.

Setters

A setter is a method that sets the value of a specific property.

const person = {
  firstName: 'John',
  lastName: 'Doe',
  set fullName(value) {
    const parts = value.split(' ');
    this.firstName = parts[0];
    this.lastName = parts[1];
  }
};

person.fullName = 'Jane Smith';
console.log(person.firstName); // Jane
console.log(person.lastName); // Smith

In the example above, we have a person object with a fullName setter. When we call person.fullName = 'Jane Smith', the set method is executed and sets the value of firstName and lastName. The set method is called without using parentheses. It looks like we are assigning a value to a property, but in reality, we are calling a method.

Getters and Setters in classes

We can also use getters and setters in classes.

class Person {
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }

  get fullName() {
    return this.firstName + ' ' + this.lastName;
  }

  set fullName(value) {
    const parts = value.split(' ');
    this.firstName = parts[0];
    this.lastName = parts[1];
  }
}

const person = new Person('John', 'Doe');
console.log(person.fullName); // John Doe
person.fullName = 'Jane Smith';
console.log(person.firstName); // Jane
console.log(person.lastName); // Smith

In the example above, we have a Person class with a fullName getter and setter. We can use them just like we did with the object.

Comparisons with Python

In Python, we can use the @property decorator to define getters and setters. The syntax is different, but the concept is the same.

class Person:
    def __init__(self, first_name, last_name):
        self.first_name = first_name
        self.last_name = last_name

    @property
    def full_name(self):
        return f'{self.first_name} {self.last_name}'

    @full_name.setter
    def full_name(self, value):
        parts = value.split(' ')
        self.first_name = parts[0]
        self.last_name = parts[1]

person = Person('John', 'Doe')
print(person.full_name) # John Doe
person.full_name = 'Jane Smith'
print(person.first_name) # Jane
print(person.last_name) # Smith

In the example above, we have a Person class with a full_name getter and setter. We can use them just like we did with the JavaScript class.

However, in Python, we can only define getters and setters for class properties. In JavaScript, we can define them for object properties as well. In other words, in Python we don't have the option to create a dict with getters and setters. In JavaScript, we can (the equivalent of a dict in JavaScript is called an object).