59 lines
2.2 KiB
Markdown
59 lines
2.2 KiB
Markdown
|
---
|
|||
|
|
id: 587d7dae367417b2b2512b7b
|
|||
|
|
title: Understand Own Properties
|
|||
|
|
challengeType: 1
|
|||
|
|
videoUrl: ''
|
|||
|
|
localeTitle: 了解自己的属性
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
## Description
|
|||
|
|
<section id="description">在以下示例中， <code>Bird</code>构造函数定义了两个属性： <code>name</code>和<code>numLegs</code> ： <blockquote> function Bird（name）{ <br> this.name = name; <br> this.numLegs = 2; <br> } <br><br>让鸭子=新鸟（“唐纳德”）; <br>让金丝雀=新鸟（“特威蒂”）; </blockquote> <code>name</code>和<code>numLegs</code>称为<code>own</code>属性，因为它们直接在实例对象上定义。这意味着<code>duck</code>和<code>canary</code>每个都有自己独立的这些属性的副本。事实上， <code>Bird</code>每个实例都有自己的这些属性的副本。下面的代码将所有的<code>own</code>的性质<code>duck</code>到阵列<code>ownProps</code> ： <blockquote>让ownProps = []; <br><br> for（let duck in duck）{ <br> if（duck.hasOwnProperty（property））{ <br> ownProps.push（属性）; <br> } <br> } <br><br>的console.log（ownProps）; //打印[“name”，“numLegs”] </blockquote></section>
|
|||
|
|
|
|||
|
|
## Instructions
|
|||
|
|
<section id="instructions">将<code>canary</code> <code>own</code>属性添加到数组<code>ownProps</code> 。 </section>
|
|||
|
|
|
|||
|
|
## Tests
|
|||
|
|
<section id='tests'>
|
|||
|
|
|
|||
|
|
```yml
|
|||
|
|
tests:
|
|||
|
|
- text: <code>ownProps</code>应包含值<code>"numLegs"</code>和<code>"name"</code> 。
|
|||
|
|
testString: 'assert(ownProps.indexOf("name") !== -1 && ownProps.indexOf("numLegs") !== -1, "<code>ownProps</code> should include the values <code>"numLegs"</code> and <code>"name"</code>.");'
|
|||
|
|
- text: 无需使用内置方法<code>Object.keys()</code>即可解决此挑战。
|
|||
|
|
testString: 'assert(!/\Object.keys/.test(code), "Solve this challenge without using the built in method <code>Object.keys()</code>.");'
|
|||
|
|
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
</section>
|
|||
|
|
|
|||
|
|
## Challenge Seed
|
|||
|
|
<section id='challengeSeed'>
|
|||
|
|
|
|||
|
|
<div id='js-seed'>
|
|||
|
|
|
|||
|
|
```js
|
|||
|
|
function Bird(name) {
|
|||
|
|
this.name = name;
|
|||
|
|
this.numLegs = 2;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
let canary = new Bird("Tweety");
|
|||
|
|
let ownProps = [];
|
|||
|
|
// Add your code below this line
|
|||
|
|
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
</section>
|
|||
|
|
|
|||
|
|
## Solution
|
|||
|
|
<section id='solution'>
|
|||
|
|
|
|||
|
|
```js
|
|||
|
|
// solution required
|
|||
|
|
```
|
|||
|
|
</section>
|