I finally managed to update #Litespread to the latest react-scripts version. With all versions between 2.0 and 3.2 I had problems getting the sqlite.js working in the production build.
Let me know how these slightly faster SQL-Spreadsheets work for you: https://www.litespread.com.
Don't hesitate to ask when encountering problems. Documentation is mostly missing and error handling needs some more work, too.