freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/regular-expressions/match-single-character-with-multiple-possibilities.english.md

id, title, challengeType, forumTopicId

id	title	challengeType	forumTopicId
587d7db5367417b2b2512b95	Match Single Character with Multiple Possibilities	1	301357

Description

You learned how to match literal patterns (/literal/) and wildcard character (/./). Those are the extremes of regular expressions, where one finds exact matches and the other matches everything. There are options that are a balance between the two extremes. You can search for a literal pattern with some flexibility with character classes. Character classes allow you to define a group of characters you wish to match by placing them inside square ([ and ]) brackets. For example, you want to match "bag", "big", and "bug" but not "bog". You can create the regex /b[aiu]g/ to do this. The [aiu] is the character class that will only match the characters "a", "i", or "u".

let bigStr = "big";
let bagStr = "bag";
let bugStr = "bug";
let bogStr = "bog";
let bgRegex = /b[aiu]g/;
bigStr.match(bgRegex); // Returns ["big"]
bagStr.match(bgRegex); // Returns ["bag"]
bugStr.match(bgRegex); // Returns ["bug"]
bogStr.match(bgRegex); // Returns null

Instructions

Use a character class with vowels (a, e, i, o, u) in your regex vowelRegex to find all the vowels in the string quoteSample. Note
Be sure to match both upper- and lowercase vowels.

Tests

tests:
  - text: You should find all 25 vowels.
    testString: assert(result.length == 25);
  - text: Your regex <code>vowelRegex</code> should use a character class.
    testString: assert(/\[.*\]/.test(vowelRegex.source));
  - text: Your regex <code>vowelRegex</code> should use the global flag.
    testString: assert(vowelRegex.flags.match(/g/).length == 1);
  - text: Your regex <code>vowelRegex</code> should use the case insensitive flag.
    testString: assert(vowelRegex.flags.match(/i/).length == 1);
  - text: Your regex should not match any consonants.
    testString: assert(!/[b-df-hj-np-tv-z]/gi.test(result.join()));

Challenge Seed

let quoteSample = "Beware of bugs in the above code; I have only proved it correct, not tried it.";
let vowelRegex = /change/; // Change this line
let result = vowelRegex; // Change this line

Solution

let quoteSample = "Beware of bugs in the above code; I have only proved it correct, not tried it.";
let vowelRegex = /[aeiou]/gi; // Change this line
let result = quoteSample.match(vowelRegex); // Change this line