> 1 metre + 8 chain = 161.9344 m
> 1 tonne + 1 short ton = 1.90718474 t
> 1 tonne + 1 long ton = 2.0160469 t
and give it a pass for not supporting pre 1963 UK | US historic weights and measures .. that's getting into a pretty specific use case where Standards nerds like to have a clear display of what conversion factors are in play and what provenance those factors have.
Time Zone support (on your About ToDo) will be interesting, historic computations with daytime savings support will be a quagmnire :-)
The SHARE DOC URLs seem a bit long - something like "base64 full text of doc as an URL" I guess.
Will this hit a URL length limit if widespread use becomes a thing?
jq play : https://jqplay.org/s/f1r-BZ5xYd2
regex101 : https://regex101.com/r/OqojJl/1
do server side storage and doc hash .. which has issues of its own.