freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/es6/use-class-syntax-to-define-a-constructor-function.english.md

id, title, challengeType, forumTopicId

id	title	challengeType	forumTopicId
587d7b8b367417b2b2512b53	Use class Syntax to Define a Constructor Function	1	301212

Description

ES6 provides a new syntax to create objects, using the class keyword. It should be noted that the class syntax is just syntax, and not a full-fledged class-based implementation of an object-oriented paradigm, unlike in languages such as Java, Python, Ruby, etc. In ES5, we usually define a constructor function and use the new keyword to instantiate an object.

var SpaceShuttle = function(targetPlanet){
  this.targetPlanet = targetPlanet;
}
var zeus = new SpaceShuttle('Jupiter');

The class syntax simply replaces the constructor function creation:

class SpaceShuttle {
  constructor(targetPlanet) {
    this.targetPlanet = targetPlanet;
  }
}
const zeus = new SpaceShuttle('Jupiter');

It should be noted that the class keyword declares a new function, to which a constructor is added. This constructor is invoked when new is called to create a new object.
Notes:

• UpperCamelCase should be used by convention for ES6 class names, as in SpaceShuttle used above.
• The constructor method is a special method for creating and initializing an object created with a class. You will learn more about it in the Object Oriented Programming section of the JavaScript Algorithms And Data Structures Certification.

Instructions

Use the class keyword and write a constructor to create the Vegetable class. The Vegetable class allows you to create a vegetable object with a property name that gets passed to the constructor.

Tests

tests:
  - text: <code>Vegetable</code> should be a <code>class</code> with a defined <code>constructor</code> method.
    testString: assert(typeof Vegetable === 'function' && typeof Vegetable.constructor === 'function');
  - text: <code>class</code> keyword should be used.
    testString: assert(code.match(/class/g));
  - text: <code>Vegetable</code> should be able to be instantiated.
    testString: assert(() => {const a = new Vegetable("apple"); return typeof a === 'object';});
  - text: <code>carrot.name</code> should return <code>carrot</code>.
    testString: assert(carrot.name=='carrot');

Challenge Seed

// Only change code below this line

// Only change code above this line

const carrot = new Vegetable('carrot');
console.log(carrot.name); // Should display 'carrot'

Solution

class Vegetable {
  constructor(name) {
    this.name = name;
  }
}
const carrot = new Vegetable('carrot');