In the challenge Regular Expressions: Match Single Character with Multiple Possibilities, the example code shows
let bgRegex = /b[aiu]g/;
which would normally work. However, the solution,
let vowelRegex = /[aeiou]/gi;
requires the global and ignore case flags to be outside the literal regex.
If done as
let vowelRegex = /[aeiou]gi/;
an empty array is returned.
I thought I would mention this in case someone was confused on what to do.