Today I came across Regular Expressions , or Regex in a case where I needed to work with finding vowels in a string. I was able to use the below
var regex = /[aeiou]/gi;
learning that gi stands for global match and case insensitive and the brackets  will only look for the characters within them.
Here are some helpful links and cheat sheets for regex:
Regexone.com <– Super helpful , I like the practice exercises with each lesson.