64 lines
1.9 KiB
Markdown
64 lines
1.9 KiB
Markdown
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---
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id: af7588ade1100bde429baf20
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title: Missing letters
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isRequired: true
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challengeType: 5
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videoUrl: ''
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localeTitle: 遗失的信件
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---
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## Description
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<section id="description">在传递的字母范围内找到丢失的字母并将其返回。如果范围内存在所有字母，则返回undefined。如果卡住，请记得使用<a href="http://forum.freecodecamp.org/t/how-to-get-help-when-you-are-stuck/19514" target="_blank">Read-Search-Ask</a> 。尝试配对程序。编写自己的代码。 </section>
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## Instructions
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<section id="instructions">
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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>fearNotLetter("abce")</code>应返回“d”。
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testString: 'assert.deepEqual(fearNotLetter("abce"), "d", "<code>fearNotLetter("abce")</code> should return "d".");'
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- text: <code>fearNotLetter("abcdefghjklmno")</code>应该返回“i”。
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testString: 'assert.deepEqual(fearNotLetter("abcdefghjklmno"), "i", "<code>fearNotLetter("abcdefghjklmno")</code> should return "i".");'
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- text: <code>fearNotLetter("stvwx")</code>应该返回“u”。
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testString: 'assert.deepEqual(fearNotLetter("stvwx"), "u", "<code>fearNotLetter("stvwx")</code> should return "u".");'
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- text: <code>fearNotLetter("bcdf")</code>应返回“e”。
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testString: 'assert.deepEqual(fearNotLetter("bcdf"), "e", "<code>fearNotLetter("bcdf")</code> should return "e".");'
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- text: <code>fearNotLetter("abcdefghijklmnopqrstuvwxyz")</code>应返回undefined。
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testString: 'assert.isUndefined(fearNotLetter("abcdefghijklmnopqrstuvwxyz"), "<code>fearNotLetter("abcdefghijklmnopqrstuvwxyz")</code> should return undefined.");'
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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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function fearNotLetter(str) {
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return str;
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}
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fearNotLetter("abce");
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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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