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

title, id, challengeType

title	id	challengeType
Generate lower case ASCII alphabet	5a23c84252665b21eecc7e7a	5

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 ['a','b','c','d'].

Instructions

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>.");'

Challenge Seed

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

After Test

console.info('after the test');

Solution

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);

}