Unicode and mbstring

[carlosmintfan]

Hi,
first, thank you for building this project!
https://locutus.io/php/strings/substr uses unicode.semantics which is an old PHP6 directive. Would you accept a PR that removes all that stuff and introduces mb_ functions?

[carlosmintfan]

Same for strlen etc.
As for strlen, it returns str.length if the iniVal is off. However, 'ä'.length is 1 in JavaScript (at least modern; was it different some years ago?) while strlen('ä') is 2 in PHP. Would you mind adopting or letting me adopt this function to do exactly what PHP does?

[carlosmintfan]

Oh, and

php > echo strtoupper("ä");
ä
php > echo mb_strtoupper("ä");
Ä
php >

while in Node:

> 'ä'.toUpperCase();
'Ä'
> 

Is there any function in Node and browsers that acts like PHP's strtoupper so we get the exact the effect?
On the other hand, perhaps these non-mb functions should be considered garbage anyway?
What's toLocaleUpperCase for in JS if toUpperCase already does it right? ChatGPT told me. It's necessary in languages like Turkish.