152 lines
4.2 KiB
Markdown
152 lines
4.2 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244cb
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/c9yNMfR'
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forumTopicId: 18208
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localeTitle: 操作复杂对象
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---
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## Description
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<section id='description'>
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有时你可能希望将数据存储在灵活的<dfn>数据结构</dfn>中。JavaScript 对象是处理灵活数据的一种方法。它可以储存<dfn>字符串</dfn>，<dfn>数字</dfn>，<dfn>布尔值</dfn>，<dfn>函数</dfn>，和<dfn>对象</dfn>以及这些值的任意组合。
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这是一个复杂数据结构的示例：
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```js
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var ourMusic = [
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{
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"artist": "Daft Punk",
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"title": "Homework",
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"release_year": 1997,
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"formats": [
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"CD",
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"Cassette",
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"LP"
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],
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"gold": true
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}
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];
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```
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这是一个对象数组，并且对象有各种关于专辑的 <dfn>详细信息</dfn>。它也有一个嵌套的<code>formats</code>的数组。附加专辑记录可以被添加到数组的最上层。
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对象将数据以一种键-值对的形式保存。在上面的示例中，<code>"artist": "Daft Punk"</code>是一个具有<code>"artist"</code>键和<code>"Daft Punk"</code>值的属性。
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<a href='http://www.json.org/' target=_blank>JavaScript Object Notation</a> 简称<code>JSON</code>是用于存储数据的相关数据交换格式。
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```json
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{
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"artist": "Daft Punk",
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"title": "Homework",
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"release_year": 1997,
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"formats": [
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"CD",
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"Cassette",
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"LP"
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],
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"gold": true
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}
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```
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<strong>提示</strong><br>数组中有多个 JSON 对象的时候，对象与对象之间要用逗号隔开。
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</section>
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## Instructions
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<section id='instructions'>
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添加一个新专辑到<code>myMusic</code>的JSON对象。添加<code>artist</code>和<code>title</code>字符串，<code>release_year</code>数字和<code>formats</code>字符串数组。
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>myMusic</code>应该是一个数组。
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testString: assert(Array.isArray(myMusic));
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- text: <code>myMusic</code>应该至少包含两个元素。
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testString: assert(myMusic.length > 1);
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- text: <code>myMusic[1]</code>应该是一个对象。
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testString: assert(typeof myMusic[1] === 'object');
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- text: <code>myMusic[1]</code>至少要包含四个属性。
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testString: assert(Object.keys(myMusic[1]).length > 3);
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- text: <code>myMusic[1]</code>应该包含一个类型为字符串的<code>artist</code>的属性。
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testString: assert(myMusic[1].hasOwnProperty('artist') && typeof myMusic[1].artist === 'string');
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- text: <code>myMusic[1]</code>应该包含一个类型为字符串的<code>title</code>的属性。
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testString: assert(myMusic[1].hasOwnProperty('title') && typeof myMusic[1].title === 'string');
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- text: <code>myMusic[1]</code>应该包含一个类型为数字的<code>release_year</code> 应该包含一个类型为数字的属性。
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testString: assert(myMusic[1].hasOwnProperty('release_year') && typeof myMusic[1].release_year === 'number');
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- text: <code>myMusic[1]</code>应该包含一个类型为数组的<code>formats</code>属性。
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testString: assert(myMusic[1].hasOwnProperty('formats') && Array.isArray(myMusic[1].formats));
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- text: <code>formats</code>应该是一个至少包含两个字符串元素的数组。
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testString: assert(myMusic[1].formats.every(function(item) { return (typeof item === "string")}) && myMusic[1].formats.length > 1);
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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var myMusic = [
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{
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"artist": "Billy Joel",
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"title": "Piano Man",
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"release_year": 1973,
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"formats": [
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"CD",
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"8T",
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"LP"
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],
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"gold": true
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}
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// Add record here
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];
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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(function(x){ if (Array.isArray(x)) { return JSON.stringify(x); } return "myMusic is not an array"})(myMusic);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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var myMusic = [
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{
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"artist": "Billy Joel",
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"title": "Piano Man",
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"release_year": 1973,
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"formats": [
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"CS",
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"8T",
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"LP" ],
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"gold": true
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},
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{
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"artist": "ABBA",
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"title": "Ring Ring",
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"release_year": 1973,
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"formats": [
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"CS",
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"8T",
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"LP",
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"CD",
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]
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}
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];
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```
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</section>
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