--- id: 587d7b8b367417b2b2512b53 title: Use class Syntax to Define a Constructor Function challengeType: 1 --- ## Description <section id='description'> ES6 provides a new syntax to help create objects, using the keyword <dfn>class</dfn>. This is to be noted, that the <code>class</code> 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 <code>new</code> keyword to instantiate an object. <blockquote>var SpaceShuttle = function(targetPlanet){<br> this.targetPlanet = targetPlanet;<br>}<br>var zeus = new SpaceShuttle('Jupiter');</blockquote> The class syntax simply replaces the constructor function creation: <blockquote>class SpaceShuttle {<br> constructor(targetPlanet) {<br> this.targetPlanet = targetPlanet;<br> }<br>}<br>const zeus = new SpaceShuttle('Jupiter');</blockquote> Notice that the <code>class</code> keyword declares a new function, and a constructor was added, which would be invoked when <code>new</code> is called - to create a new object.<br> <strong>Notes:</strong><br><ul> <li> UpperCamelCase should be used by convention for ES6 class names, as in <code>SpaceShuttle</code> used above.</li> <li> 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.</li></ul> </section> ## Instructions <section id='instructions'> Use <code>class</code> keyword and write a proper constructor to create the <code>Vegetable</code> class. The <code>Vegetable</code> lets you create a vegetable object, with a property <code>name</code>, to be passed to constructor. </section> ## Tests <section id='tests'> ```yml 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'); ``` </section> ## Challenge Seed <section id='challengeSeed'> <div id='js-seed'> ```js /* Alter code below this line */ /* Alter code above this line */ const carrot = new Vegetable('carrot'); console.log(carrot.name); // => should be 'carrot' ``` </div> </section> ## Solution <section id='solution'> ```js class Vegetable { constructor(name) { this.name = name; } } const carrot = new Vegetable('carrot'); ``` </section>