Object creation - JavaScript Challenges

You can find all the code in this post in the repo Github.

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Object creation methods

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Class-based

Recommend after ES6.

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

  greet() {
    console.log(`Hello, my name is ${this.firstName} ${this.lastName}`);
  }
}

// Usage example
const person1 = new Person("John", "Doe", 30);
person1.greet(); // => 'Hello, my name is John Doe'

const person2 = new Person("Jane", "Smith", 25);
person2.greet(); // => 'Hello, my name is Jane Smith'

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Constructor-based

Recommend before ES6.

/**
 * @param {string} firstName
 * @param {string} lastName
 * @param {number} age
 */

function Person(firstName, lastName, age) {
  this.firstName = firstName;
  this.lastName = lastName;
  this.age = age;
  this.greet = function () {
    console.log(`Hello, my name is ${this.firstName} ${this.lastName}`);
  };
}

// Usage example
const person1 = new Person("John", "Doe", 30);
person1.greet(); // => Hello, my name is John Doe

const person2 = new Person("Jane", "Smith", 25);
person2.greet(); // => Hello, my name is Jane Smith

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Object literals

{}

const person = {
  firstName: "John",
  lastName: "Doe",
  age: 30,
  greet: function () {
    console.log(`Hello, my name is ${this.firstName} ${this.lastName}`);
  },
};

person.greet(); // => 'Hello, my name is John Doe'

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Object.create()

The Object.create() static method creates a new object, using an existing object as the prototype of the newly created object. - MDN

const personPrototype = {
  greet: function () {
    console.log(`Hello, my name is ${this.firstName} ${this.lastName}`);
  },
};

const person = Object.create(personPrototype);
person.firstName = "John";
person.lastName = "Doe";

// Usage example
person.greet(); // => 'Hello, my name is John Doe'

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Factory Pattern

/**
 * @param {string} firstName
 * @param {string} lastName
 * @param {number} age
 * @return {object}
 */

function createPerson(firstName, lastName, age) {
  return {
    firstName: firstName,
    lastName: lastName,
    age: age,
    greet: function () {
      console.log(`Hello, my name is ${this.firstName} ${this.lastName}`);
    },
  };
}

// Usage example
const person1 = createPerson("John", "Doe", 30);
person1.greet(); // => 'Hello, my name is John Doe'

const person2 = createPerson("Jane", "Smith", 25);
person2.greet(); // => 'Hello, my name is Jane Smith'

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Reference

• Classes - MDN
• Object-oriented programming - MDN
• Object-oriented programming - MDN
• Object initializer - MDN
• Object.create() - MDN
• Factory Pattern - patterns.dev