curriculum/challenges/english/blocks/regular-expressions/587d7db5367417b2b2512b95.md
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 <dfn>character classes</dfn>. 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);
bagStr.match(bgRegex);
bugStr.match(bgRegex);
bogStr.match(bgRegex);
In order, the four match calls would return the values ["big"], ["bag"], ["bug"], and null.
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.
You should find all 25 vowels.
assert(result.length == 25);
Your regex vowelRegex should use a character class.
assert(/\[.*\]/.test(vowelRegex.source));
Your regex vowelRegex should use the global flag.
assert(vowelRegex.flags.match(/g/).length == 1);
Your regex vowelRegex should use the case insensitive flag.
assert(vowelRegex.flags.match(/i/).length == 1);
Your regex should not match any consonants.
assert(!/[b-df-hj-np-tv-z]/gi.test(result.join()));
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
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