🔧 true-form-length: A Library for Accurate Character Counting in Web Forms

Background


I previously wrote about the hidden pitfalls in JavaScript character counting. The issues go beyond the well-known surrogate pair problem:




Issue
JS .length

Server receives




Emoji 🎉

2
1 character



a\nb\nc (textarea)
5
7 chars (\n → \r\n)


Lone surrogate \uD800

1
MySQL error 💥




That last one is especially problematic—a...