What Excel is
An Excel workbook is a zip archive of XML parts describing sheets, cells, formulas, styles and charts. The .xlsx extension is that format; .xls is the older binary one from before 2007.
Finance, operations and anyone who received a file from finance or operations.
What ActionScript is
An ActionScript Array of object literals.
Legacy Flash and AIR projects.
What changes when you convert Excel to ActionScript
Only the first sheet is read, and cells are read as the text Excel displays rather than the number underneath. That matters for dates: a cell showing 15/03/2026 arrives as that string, not as a serial number you would then have to decode.
Typed as Array, with double-quoted string values.
What carries over from Excel to ActionScript
Excel records 2 things about a table that ActionScript has no way to hold.
ActionScript has no header row. The column names are repeated as keys on every record instead, which is why the result is bigger on disk than the table it came from.
Anything visual in the Excel - weight, alignment, colour, column widths - has no counterpart in ActionScript and is dropped. The values are what survives.
Both formats record types, so numbers, booleans and nulls survive as themselves rather than as text.