--- id: 587d7b8b367417b2b2512b53 title: Verwende die Klassensyntax, um eine Konstruktorfunktion zu definieren challengeType: 1 forumTopicId: 301212 dashedName: use-class-syntax-to-define-a-constructor-function --- # --description-- ES6 bietet eine neue Syntax zum Erstellen von Objekten, die das Schlüsselwort class verwendet. In ES5, an object can be created by defining a `constructor` function and using the `new` keyword to instantiate the object. In ES6, a `class` declaration has a `constructor` method that is invoked with the `new` keyword. If the `constructor` method is not explicitly defined, then it is implicitly defined with no arguments. ```js // Explicit constructor class SpaceShuttle { constructor(targetPlanet) { this.targetPlanet = targetPlanet; } takeOff() { console.log("To " + this.targetPlanet + "!"); } } // Implicit constructor class Rocket { launch() { console.log("To the moon!"); } } const zeus = new SpaceShuttle('Jupiter'); // prints To Jupiter! in console zeus.takeOff(); const atlas = new Rocket(); // prints To the moon! in console atlas.launch(); ``` 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. **Note:** 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`. # --hints-- `Vegetable` should be a `class` with a defined `constructor` method. ```js assert( typeof Vegetable === 'function' && typeof Vegetable.constructor === 'function' ); ``` The `class` keyword should be used. ```js assert(code.match(/class/g)); ``` `Vegetable` should be able to be instantiated. ```js assert(() => { const a = new Vegetable('apple'); return typeof a === 'object'; }); ``` `carrot.name` should return `carrot`. ```js assert(carrot.name == 'carrot'); ``` # --seed-- ## --seed-contents-- ```js // Only change code below this line // Only change code above this line const carrot = new Vegetable('carrot'); console.log(carrot.name); // Should display 'carrot' ``` # --solutions-- ```js class Vegetable { constructor(name) { this.name = name; } } const carrot = new Vegetable('carrot'); ```