76 lines
2.3 KiB
Markdown
76 lines
2.3 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244c7
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title: Accessing Object Properties with Dot Notation
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challengeType: 1
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videoUrl: ''
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localeTitle: 使用点表示法访问对象属性
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---
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## Description
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<section id="description">有两种方法可以访问对象的属性：点表示法（ <code>.</code> ）和括号表示法（ <code>[]</code> ），类似于数组。当您知道要提前访问的属性的名称时，使用点符号。以下是使用点表示法（ <code>.</code> ）读取对象属性的示例： <blockquote> var myObj = { <br> prop1：“val1”， <br> prop2：“val2” <br> }; <br> var prop1val = myObj.prop1; // val1 <br> var prop2val = myObj.prop2; // val2 </blockquote></section>
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## Instructions
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<section id="instructions">使用点表示法读入<code>testObj</code>的属性值。将变量<code>hatValue</code>设置为等于对象的属性<code>hat</code> ，并将变量<code>shirtValue</code>设置为等于对象的属性<code>shirt</code> 。 </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>hatValue</code>应该是一个字符串
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testString: 'assert(typeof hatValue === "string" , "<code>hatValue</code> should be a string");'
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- text: <code>hatValue</code>的值应该是<code>"ballcap"</code>
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testString: 'assert(hatValue === "ballcap" , "The value of <code>hatValue</code> should be <code>"ballcap"</code>");'
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- text: <code>shirtValue</code>应该是一个字符串
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testString: 'assert(typeof shirtValue === "string" , "<code>shirtValue</code> should be a string");'
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- text: <code>shirtValue</code>的值应该是<code>"jersey"</code>
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testString: 'assert(shirtValue === "jersey" , "The value of <code>shirtValue</code> should be <code>"jersey"</code>");'
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- text: 你应该使用点符号两次
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testString: 'assert(code.match(/testObj\.\w+/g).length > 1, "You should use dot notation twice");'
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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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// Setup
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var testObj = {
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"hat": "ballcap",
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"shirt": "jersey",
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"shoes": "cleats"
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};
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// Only change code below this line
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var hatValue = testObj; // Change this line
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var shirtValue = testObj; // Change this line
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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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console.info('after the test');
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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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// solution required
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```
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</section>
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