regex start and end with same vowel code example

Example 1: match a string that starts and ends with the same vowel

const regex = /\b(?<vowel>[aeiou])(\w*\k<vowel>)?\b/

Example 2: Find a vowel at the begining and end with regular expression

//  ^ => first item matches:
// () => stores matching value captured within
// [aeiou] => matches any of the characters in the brackets
// . => matches any character:
// + => for 1 or more occurrances (this ensures str length > 3)
// \1 => matches to previously stored match. 
    // \2 looks for matched item stored 2 instances ago 
    // \3 looks for matched item stored 3 ago, etc

//  $ ensures that matched item is at end of the sequence

let re = /^([aeiou]).*\1$/i;

return re;

}