docs.sheetjs.com/docbits/51_cell.md

Cell Object

Cell objects are plain JS objects with keys and values following the convention:

Key	Description
v	raw value (see Data Types section for more info)
w	formatted text (if applicable)
t	type: b Boolean, e Error, n Number, d Date, s Text, z Stub
f	cell formula encoded as an A1-style string (if applicable)
F	range of enclosing array if formula is array formula (if applicable)
D	if true, array formula is dynamic (if applicable)
r	rich text encoding (if applicable)
h	HTML rendering of the rich text (if applicable)
c	comments associated with the cell
z	number format string associated with the cell (if requested)
l	cell hyperlink object (.Target holds link, .Tooltip is tooltip)
s	the style/theme of the cell (if applicable)

Built-in export utilities (such as the CSV exporter) will use the w text if it is available. To change a value, be sure to delete cell.w (or set it to undefined) before attempting to export. The utilities will regenerate the w text from the number format (cell.z) and the raw value if possible.

The actual array formula is stored in the f field of the first cell in the array range. Other cells in the range will omit the f field.