2021-02-06 04:42:36 +00:00
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---
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id: af7588ade1100bde429baf20
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2021-03-22 13:52:28 +00:00
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title: Letras faltantes
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2021-02-06 04:42:36 +00:00
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challengeType: 5
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forumTopicId: 16023
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dashedName: missing-letters
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---
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# --description--
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2021-03-22 13:52:28 +00:00
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Encuentra la letra que falta en la siguiente cadena de letras y devuélvela.
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2021-02-06 04:42:36 +00:00
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2021-03-22 13:52:28 +00:00
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Si todas las letras están presentes en la cadena, devuelve `undefined`.
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2021-02-06 04:42:36 +00:00
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# --hints--
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2021-03-22 13:52:28 +00:00
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`fearNotLetter("abce")` debe devolver la cadena `d`.
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2021-02-06 04:42:36 +00:00
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```js
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assert.deepEqual(fearNotLetter('abce'), 'd');
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```
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2021-03-22 13:52:28 +00:00
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`fearNotLetter("abcdefghjklmno")` debe devolver la cadena `i`.
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2021-02-06 04:42:36 +00:00
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```js
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assert.deepEqual(fearNotLetter('abcdefghjklmno'), 'i');
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```
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2021-03-22 13:52:28 +00:00
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`fearNotLetter("stvwx")` debe devolver la cadena `u`.
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2021-02-06 04:42:36 +00:00
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```js
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assert.deepEqual(fearNotLetter('stvwx'), 'u');
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```
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2021-03-22 13:52:28 +00:00
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`fearNotLetter("bcdf")` debe devolver la cadena `e`.
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2021-02-06 04:42:36 +00:00
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```js
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assert.deepEqual(fearNotLetter('bcdf'), 'e');
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```
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2021-03-22 13:52:28 +00:00
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`fearNotLetter("abcdefghijklmnopqrstuvwxyz")` debe devolver `undefined`.
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2021-02-06 04:42:36 +00:00
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```js
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assert.isUndefined(fearNotLetter('abcdefghijklmnopqrstuvwxyz'));
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```
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# --seed--
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## --seed-contents--
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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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# --solutions--
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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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