XLSX Tax Rules Editor

Spreadsheet-first editor to define input schemas (types + tables/columns) and calculation rules as JavaScript, then generate an end-user XLSX template, validate filled templates, and simulate results locally.

This project exists to help translate real-world tax logic (often maintained in spreadsheets) into code in an iterative, testable workflow.

What you can do

• Define input types: parsing/formatting and optional entity references (FKs).
• Define tables & columns: model the workbook structure your end users will fill.
• Define rules (JS): executed top-to-bottom to produce computed outputs.
• Export two artifacts:
  • Business-logic workbook (.xlsx): types + columns + rules.
  • Template workbook (.template.xlsx): end-user data entry workbook.
• Validate + simulate: upload a filled template, validate it, then run the rule pipeline and inspect results.
• AI-assisted editing (optional): generate/edit types, tables, and rules through the UI (requires an API key).

Intended workflow

1. Create/open a business-logic workbook
2. Edit:
   • InputType sheet (types + parse/format JS)
   • Column sheet (tables + columns)
   • Rule sheet (rule JS)
3. Click Generate template XLSX
4. Fill the template with test data in Excel/LibreOffice
5. Upload it via Template + Simulation
6. Click Validate + Run sim and review errors/results

Getting started

Prerequisites

• Node.js (recommended: current LTS)
• pnpm

Install & run

pnpm install
pnpm dev

Then open the URL printed by the dev server.

Tests

pnpm test
pnpm test:ui

• pnpm test: domain/unit tests (Node’s built-in test runner).
• pnpm test:ui: frontend “e2e-style” integration tests in JSDOM (no Playwright/Chrome required).

AI configuration (optional)

Some UI actions call Next.js API routes under app/api/ai/*.

Set:

export OPENAI_API_KEY="..."

If OPENAI_API_KEY is missing, the AI endpoints will return an error and the rest of the app remains usable.

License

GPL-3.0. See LICENSE.md.