Separate storage precision from spreadsheet display
A 64-bit integer can represent values outside the exact integer range of JavaScript Number and beyond typical spreadsheet numeric precision. Identifiers are particularly easy to damage because they often look like ordinary numbers. Parquet Desk reads those integer values as BigInt and exports their decimal spelling as text.
DECIMAL values also need their scale. The physical representation stores an unscaled signed integer; the converter inserts the decimal point using integer arithmetic. A value such as 12.340000 therefore retains its declared fractional digits. It is not converted to a floating-point number and later reformatted to look precise.
Choose formats with an import policy
The XLSX workbook writes literal text cells for exported values, with a separate schema sheet. Typed JSON retains the schema, selected rows, null values and nested structures. Its numeric values are strings by design; use the type information when loading them into a destination system. Boolean values remain Boolean values in JSON.
CSV has no field-type metadata. A spreadsheet can strip leading zeros or round large values even when a CSV cell is quoted. Import identifier and exact-number columns as text and keep the schema manifest with the file. Formula-like CSV values receive a protective apostrophe, while XLSX and JSON retain the original value.
Do not silently change time semantics
DATE, TIME and TIMESTAMP have units and sometimes UTC-adjustment semantics. Converting everything to a JavaScript Date can discard microseconds or nanoseconds, and a local timestamp does not identify a timezone by itself. This release retains exact integer units and records their meaning in the schema.
Convert those values deliberately in your destination tool using the declared unit and application context. Floating-point columns remain their stored floating-point values represented as round-trippable text; special values such as NaN, infinity and negative zero have explicit spellings. Exact decimal handling does not turn an already approximate FLOAT or DOUBLE into a decimal measurement.