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

id, title, challengeType

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

Description

ES6 provides a new syntax to help create objects, using the keyword class. This is to be noted, that the class syntax is just a syntax, and not a full-fledged class based implementation of object oriented paradigm, unlike in languages like Java, or Python, or 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');

Notice that the class keyword declares a new function, and a constructor was added, which would be 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 class keyword and write a proper constructor to create the Vegetable class. The Vegetable lets you create a vegetable object, with a property name, to be passed to 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

/* Alter code below this line */

/* Alter code above this line */

const carrot = new Vegetable('carrot');
console.log(carrot.name); // => should be 'carrot'

Solution

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