read from stdin on the command line about j HOT 4 CLOSED

The bad news: there are some XLS writers in the wild that store the underlying data in ways which require seeking to the end of the file first, so there's no general way of doing this without writing to a temporary file first (I'll explain why at the end).

The good news: someone already made a module that writes to a temporary file

Why you can't generally parse XLS in a streaming manner: XLS files consist of binary sub-files within a larger container (referred to as "Compound File Binary File Format" -- https://github.com/SheetJS/js-cfb is the library that just implements parsing the container). The container is a series of blocks, and every block after the first one contains an address for the next block. The header block contains a directory for where certain files start. There is no requirement that the different blocks corresponding to a file are in order, and there is no requirement that the entire directory appear before the actual data. Some clever XLS writers exploit this behavior to allow for streaming (in the obvious way: the writer writes the data before the directory, and the receiver can calculate what the directory looks like based on the data it already received)

As a concrete example: http://svn.apache.org/repos/asf/poi/trunk/test-data/spreadsheet/45290.xls is from the POI test suite. In this case, the directory appears near the end of the file, so you'd have to basically read the entire file to parse properly.

from j.

@SheetJSDev ahhhhhhh, thanks for the explanation!

XLS is frikkin crazy. I'll definitely check out the excel-stream module, it looks like what I need

from j.

so there's no general way of doing this without writing to a temporary file first

Why can't you buffer up stdin and then read it?

from j.

@sindresorhus good point :)

from j.