Demos

Each demo runs the real engine in your browser; nothing is sent to a server. This page only links to them, so it stays light. Open the page that hosts a demo to read the surrounding explanation.

Formulas and recalculation

• Evaluate a formula: type a formula and see the engine's result, its value kind, and how errors such as #DIV/0! come back as values.
• Recalculate a workbook: load an .xlsx or generate a sample, recalculate it, and download the saved bytes. The same demo appears in Browser workbook upload.
• Dependency tracing: select a cell in a formula chain and see its precedents and dependents, with a depth control.
• Iterative calculation: solve a circular reference and watch the residual curve change as you adjust the tolerance.

Workbook features

• Dynamic arrays: preview the spill shape of an array formula, commit it to a sheet, and trigger a #SPILL! case.
• PivotTables: configure a pivot table and inspect the cells the engine projects.
• Inserting and deleting rows and columns: edit the structure and compare formulas before and after, including references that collapse to #REF!.
• XLSX and XLSB round trip: write one workbook into both containers and read each back.

Compatibility

• Function lookup: search the function catalog read from the running engine, with arity and implementation status.
• Error model: compare a formula error value with a host failure from loading invalid bytes.

formulon-cell UI

• Full spreadsheet demo: edit a seeded workbook, open menus and dialogs, switch themes and platform UI, and change which controls are visible.
• Read-only report viewer: a fixed viewport that allows only selection and copy.
• Fixed-input form: a sheet where only designated cells accept input.
• UI profiles: switch chrome and density with setUi() without remounting.
• Host updates and events: push values from the host and watch the events the sheet emits.
• Theme and locale switching: change theme and UI dictionary on a mounted sheet.
• Overlays inside a native dialog: keep the sheet and its floating UI inside one dialog boundary.