Parsing .xlsx in JS with libraries like SheetJS often means: Loading the whole 100 MB file into memory Blocking the main thread Tabs freezing, fans spinning xl

Parsing .xlsx in JS with libraries like SheetJS often means: Loading the whole 100 MB file into memory Blocking the main thread Tabs freezing, fans spinning xlsx-lite does it differently: Streams ZIP entries (no inflate-to-Vec) Async + cooperative yielding — browser paints while parsing Batch-based parsing (rows in chunks) Memory stays flat, UI stays responsive