Numina
Formulas that flow.
What it is
Numina is a reactive spreadsheet engine built around a pure formula language that tokenizes, Pratt-parses, and evaluates expressions with cell references, ranges, and functions like SUM, AVG, MIN, and MAX. The interesting part is the Sheet that resolves formulas recursively, which gives you dependency-ordered recalculation and cycle detection for free. It is a from-scratch, dependency-light build with no DOM coupling that you can download and run locally.
A pure formula language (tokenize → Pratt parse → evaluate; refs, ranges, SUM/AVG/MIN/MAX) plus a Sheet that resolves recursively - dependency-ordered recalc + cycle detection for free. 11 tests, no DOM.
What's inside
The full source, the tests, and CI. Open it, read it, change it. A zero-dependency core, free, in the MIT spirit.
Run it after unzip
pnpm install && pnpm dev