JavaScript RegEx for "Title Case" and names like McDonald

Question

I am trying to title case all of the words in a string using a RegEx.

I am using the following code (derived from another post) right now, but I think there has to be something better.

My processing is as follows:

1. Convert entire string to Lower Case
2. Convert the 1st letter of a word following a boundary (non-word character) to Upper Case
3. Handle any case where the string starts with "mc" following a boundary by converting the 3rd character to Upper Case

The code is:

    let text = "STEPHEN wells-o'shaugnessy mcdonald";
    let result = text.toLowerCase().replace(/\b\w/g,(c) => c.toUpperCase());
    result = result.replace(/\bmc\w/ig,(c) => c.charAt(0).toUpperCase() + c.charAt(1).toLowerCase() + c.charAt(2).toUpperCase());

    result is:  Stephen Well-O'Shaugnessy McDonald

I thought the following would work for names starting with "mc" but it does not, and I can't figure out why:

result = result.replace(/b(?:mc)\w/ig, (c) => c.toUpperCase());

My thought was that the "/(?:mc)" would match the characters "mc" following a boundary but ignore the match since it is a non-capturing match, globally and ignoring case

and the "\w" would match the next character

which would be converted to Upper Case in the (c) => c.toUpperCase()

Any help making this more concise and explaining why the last "replace" doesn't work would be appreciated.

Thanks,

Eric