I'm working on a similar problem. The performance for parsing/stringifying enums with holes is abysmal (in C anyway, JS is mostly fine).
The problem is getting acceptable performance without importing the tables module which is kinda huge, needs modules math, hashes and others. I tried various implementation of parseEnum and I'm settling with a variant of binary search with a lookup table. (it's within ~10-20% of hashtable for Enums with ~8000 entries) Another factor is code length, basic linear search is very short but performan badly on Enums with ~100+ entries. PR is coming once I cleanup the code.
