The original flapjs has an excellent regular expression implementation. This module can be reused. Additionally, take a look at the frontend for this module and see what can be ported.
If you think you can do one better, you can write something from scratch.
Edit: Also design a regex to DFA/NFA functionality. There are existing algos one can follow. We might want to scramble the states so people cannot use them to cheat.
The original flapjs has an excellent regular expression implementation. This module can be reused. Additionally, take a look at the frontend for this module and see what can be ported.
If you think you can do one better, you can write something from scratch.
Edit: Also design a regex to DFA/NFA functionality. There are existing algos one can follow. We might want to scramble the states so people cannot use them to cheat.