Encapsulate Variable.md

Encapsulate Variable

Why?

You have public field and you want to avoid other objects to update the value of that field.

Benefits:

• The field cannot be modify from outside.

What?

Make the field private.

How?

Make the field private and create access function for it.

Sample

Before

class Person{
    constructor(firstName, lastName, dateOfBirth){
        this.firstName = firstName;
        this.lastName = lastName;
        this.dateOfBirth = dateOfBirth;
    }
/*
    isAdult(){
        return this.getAge() >= 18;
    }

    getAge(){
        const diffMiliseconds = Date.now() - Date.parse(this.dateOfBirth);
        return new Date(diffMiliseconds).getFullYear() - 1970;
    }
*/
    getFName(){
        return this.firstName + ' ' + this.lastName;
    }
/*
    printPerson(){
        let age = this.getAge();
        this.showDetails(age);
    }

    showDetails(age){
        console.log(`name: ${this.firname}`);
        console.log(`name: ${this.lastName}`);
        console.log(`name: ${age}`);
    }
*/
}

class Person{
    #firstName;
    #lastName;
    #dateOfBirth;

    constructor(firstName, lastName, dateOfBirth){
        this.#firstName = firstName;
        this.#lastName = lastName;
        this.#dateOfBirth = dateOfBirth;
    }
/*
    isAdult(){
        return this.getAge() >= 18;
    }

    getAge(){
        const diffMiliseconds = Date.now() - Date.parse(this.#dateOfBirth);
        return new Date(diffMiliseconds).getFullYear() - 1970;
    }
*/
    get FirstName(){
        return this.#firstName;
    }

    get LastName(){
        return this.#lastName;
    }

    get FullName(){
        return this.#firstName + ' ' + this.#lastName;
    }
/*
    printPerson(){
        let age = this.getAge();
        this.showDetails(age);
    }

    showDetails(age){
        console.log(`name: ${this.firname}`);
        console.log(`name: ${this.lastName}`);
        console.log(`name: ${age}`);
    }
*/
}