Data Types and Limits

Supported cell types

tablsx normalizes cells into these logical types:

• string
• number
• boolean
• date
• empty
• formula
• vector

Use CellType when you need explicit overrides or want to validate a type name.

Dates

Dates are represented as JavaScript Date instances in the normalized model. Excel serial conversion is handled by:

• excelDateToJS
• jsDateToExcel

The implementation compensates for Excel's 1900 leap-year bug. The detailed behavior contract lives in the internal PRD rules set under prd/rules/date-handling.md.

Vectors

Numeric arrays are supported as a vector type. They are serialized using JSON string representation. The internal serialization rule is documented in prd/rules/vector-serialization.md.

Formulas

Formula cells store both a formula string and a normalized type. The package focuses on representation and round-trip behavior, not formula evaluation. The internal rationale lives in prd/adr/0006-formula-handling.md.

Current Scope Boundaries

tablsx is intentionally not a full spreadsheet editing engine. The following feature classes are currently out of scope:

• rich styling and formatting APIs
• comments, images, and advanced worksheet layout controls
• Excel UI features such as panes, validation rules, or conditional formatting

Some feature ideas remain under consideration for future scope review, but they are not currently supported. The internal feature classification lives in prd/PRD.md and prd/rules/limitations.md.