freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/rosetta-code/generate-lower-case-ascii-alphabet.english.md

---
title: Generate lower case ASCII alphabet
id: 5a23c84252665b21eecc7e7a
challengeType: 5
---

## Description
<section id='description'>
Write a function to generate an array of lower case ASCII characters, for a given range. For example: for range 1 to 4 the function should return <code>['a','b','c','d']</code>.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: "'<code>lascii</code> should be a function."'
    testString: 'assert(typeof lascii=="function","<code>lascii</code> should be a function.");'
  - text: "'<code>lascii("a","d")</code> should return an array."'
    testString: 'assert(Array.isArray(lascii("a","d")),"<code>lascii("a","d")</code> should return an array.");'
  - text: '"<code>lascii("a","d")</code> should return <code>[ "a", "b", "c", "d" ]</code>."'
    testString: 'assert.deepEqual(lascii("a","d"),results[0],"<code>lascii("a","d")</code> should return <code>[ "a", "b", "c", "d" ]</code>.");'
  - text: '"<code>lascii("c","i")</code> should return <code>[ "c", "d", "e", "f", "g", "h", "i" ]</code>."'
    testString: 'assert.deepEqual(lascii("c","i"),results[1],"<code>lascii("c","i")</code> should return <code>[ "c", "d", "e", "f", "g", "h", "i" ]</code>.");'
  - text: '"<code>lascii("m","q")</code> should return <code>[ "m", "n", "o", "p", "q" ]</code>."'
    testString: 'assert.deepEqual(lascii("m","q"),results[2],"<code>lascii("m","q")</code> should return <code>[ "m", "n", "o", "p", "q" ]</code>.");'
  - text: '"<code>lascii("k","n")</code> should return <code>[ "k", "l", "m", "n" ]</code>.")'
    testString: 'assert.deepEqual(lascii("k","n"),results[3],"<code>lascii("k","n")</code> should return <code>[ "k", "l", "m", "n" ]</code>.");'
  - text: '"<code>lascii("t","z")</code> should return <code>[ "t", "u", "v", "w", "x", "y", "z" ]</code>."'
    testString: 'assert.deepEqual(lascii("t","z"),results[4],"<code>lascii("t","z")</code> should return <code>[ "t", "u", "v", "w", "x", "y", "z" ]</code>.");'

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function lascii (cFrom, cTo) {
  // Good luck!
}
```

</div>


### After Test
<div id='js-teardown'>

```js
console.info('after the test');
```

</div>

</section>

## Solution
<section id='solution'>


```js
function lascii(cFrom, cTo) {

  function cRange(cFrom, cTo) {
    var iStart = cFrom.charCodeAt(0);

    return Array.apply(
      null, Array(cTo.charCodeAt(0) - iStart + 1)
    ).map(function (_, i) {

      return String.fromCharCode(iStart + i);

    });
  }

  return cRange(cFrom, cTo);

}

```

</section>