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.
Note
UpperCamelCase should be used by convention for ES6 class names, as in SpaceShuttle used above.

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

Challenge Seed

function makeClass() {
  "use strict";
  /* Alter code below this line */

  /* Alter code above this line */
  return Vegetable;
}
const Vegetable = makeClass();
const carrot = new Vegetable('carrot');
console.log(carrot.name); // => should be 'carrot'

Solution

function makeClass() {
  "use strict";
  /* Alter code below this line */
  class Vegetable {
    constructor(name){
      this.name = name;
    }
  }
  /* Alter code above this line */
  return Vegetable;
}
const Vegetable = makeClass();
const carrot = new Vegetable('carrot');
console.log(carrot.name); // => should be 'carrot'