freeCodeCamp/curriculum/challenges/espanol/02-javascript-algorithms-an.../es6/use-class-syntax-to-define-...

101 lines
2.5 KiB
Markdown
Raw Normal View History

---
id: 587d7b8b367417b2b2512b53
title: Use class Syntax to Define a Constructor Function
challengeType: 1
forumTopicId: 301212
dashedName: use-class-syntax-to-define-a-constructor-function
---
# --description--
ES6 provides a new syntax to create objects, using the <dfn>class</dfn> 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.
```js
var SpaceShuttle = function(targetPlanet){
this.targetPlanet = targetPlanet;
}
var zeus = new SpaceShuttle('Jupiter');
```
The `class` syntax simply replaces the constructor function creation:
```js
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.
# --hints--
`Vegetable` should be a `class` with a defined `constructor` method.
```js
assert(
typeof Vegetable === 'function' && typeof Vegetable.constructor === 'function'
);
```
`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');
```