It's neat that it's client side only but it's quite feature lacking compared to https://tiktokenizer.vercel.app/ or even a small python script I wrote.
Feedback (Feature parity): -Identification and separation of individual tokens. Useful for prompting/adjusting logit biases.
-Optional chat formatting
-It's not very responsive to type on, perhaps you could delay the token calc a little
Further suggestions (I don't know how simple you want to keep it):
-Counting tokens for Function Calling json functions