77 lines
2.1 KiB
Markdown
77 lines
2.1 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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---
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## Description
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<section id='description'>
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Find the missing letter in the passed letter range and return it.
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If all letters are present in the range, return undefined.
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Remember to use <a href='http://forum.freecodecamp.org/t/how-to-get-help-when-you-are-stuck/19514' target='_blank'>Read-Search-Ask</a> if you get stuck. Try to pair program. Write your own code.
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</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> should return "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> should return "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> should return "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> should return "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> should return 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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function fearNotLetter (str) {
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for (var i = str.charCodeAt(0); i <= str.charCodeAt(str.length - 1); i++) {
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var letter = String.fromCharCode(i);
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if (str.indexOf(letter) === -1) {
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return letter;
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}
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}
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return undefined;
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}
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```
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</section>
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