74 lines
2.4 KiB
Markdown
74 lines
2.4 KiB
Markdown
|
---
|
||
|
|
id: 587d7dad367417b2b2512b78
|
||
|
|
title: Use a Constructor to Create Objects
|
||
|
|
localeTitle: Usa un constructor para crear objetos
|
||
|
|
challengeType: 1
|
||
|
|
---
|
||
|
|
|
||
|
|
## Description
|
||
|
|
<section id='description'>
|
||
|
|
Aquí está el constructor <code>Bird</code> del desafío anterior:
|
||
|
|
<blockquote>function Bird() {<br> this.name = "Albert";<br> this.color = "blue";<br> this.numLegs = 2;<br> // "this" inside the constructor always refers to the object being created<br>}<br><br>let blueBird = new Bird();</blockquote>
|
||
|
|
Observe que el <code>new</code> operador se utiliza al llamar a un constructor. Esto le dice a JavaScript que cree una nueva <code>instance</code> de <code>Bird</code> llamada <code>blueBird</code> . Sin el <code>new</code> operador, <code>this</code> dentro del constructor no apuntaría al objeto recién creado, dando resultados inesperados.
|
||
|
|
Ahora, <code>blueBird</code> tiene todas las propiedades definidas dentro del constructor <code>Bird</code> :
|
||
|
|
<blockquote>blueBird.name; // => Albert<br>blueBird.color; // => blue<br>blueBird.numLegs; // => 2</blockquote>
|
||
|
|
Al igual que cualquier otro objeto, sus propiedades se pueden acceder y modificar:
|
||
|
|
<blockquote>blueBird.name = 'Elvira';<br>blueBird.name; // => Elvira</blockquote>
|
||
|
|
</section>
|
||
|
|
|
||
|
|
## Instructions
|
||
|
|
<section id='instructions'>
|
||
|
|
Usa el constructor <code>Dog</code> de la última lección para crear una nueva instancia de <code>Dog</code> , asignándola a un <code>hound</code> variable.
|
||
|
|
</section>
|
||
|
|
|
||
|
|
## Tests
|
||
|
|
<section id='tests'>
|
||
|
|
|
||
|
|
```yml
|
||
|
|
tests:
|
||
|
|
- text: <code>hound</code> debe ser creado usando el constructor de <code>Dog</code> .
|
||
|
|
testString: 'assert(hound instanceof Dog, "<code>hound</code> should be created using the <code>Dog</code> constructor.");'
|
||
|
|
- text: Tu código debe usar el <code>new</code> operador para crear una <code>instance</code> de <code>Dog</code> .
|
||
|
|
testString: 'assert(code.match(/new/g), "Your code should use the <code>new</code> operator to create an <code>instance</code> of <code>Dog</code>.");'
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
## Challenge Seed
|
||
|
|
<section id='challengeSeed'>
|
||
|
|
|
||
|
|
<div id='js-seed'>
|
||
|
|
|
||
|
|
```js
|
||
|
|
function Dog() {
|
||
|
|
this.name = "Rupert";
|
||
|
|
this.color = "brown";
|
||
|
|
this.numLegs = 4;
|
||
|
|
}
|
||
|
|
// Add your code below this line
|
||
|
|
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
## Solution
|
||
|
|
<section id='solution'>
|
||
|
|
|
||
|
|
|
||
|
|
```js
|
||
|
|
function Dog() {
|
||
|
|
this.name = "Rupert";
|
||
|
|
this.color = "brown";
|
||
|
|
this.numLegs = 4;
|
||
|
|
}
|
||
|
|
const hound = new Dog();
|
||
|
|
```
|
||
|
|
|
||
|
|
</section>
|