CSV.js | Full RFC 4180 compliance | Parser library

By default, feather.write_feather() uses LZ4 compression, but the javascript library does not support either of the compression standards from R/Python/C++ implementations.

If you want to be able to read using the Arrow-JS library, you must pass compression="uncompressed" as an argument when you write from Python.

Usually when I try to read a compressed feather file in JS it errors because the file is shorter than the expected number of bytes; I would guess that your data here is short enough that instead, the JS implementation is grabbing some arbitrary bytes from the footer and trying to interpret them as part of the "Numbers" column.

Figured it out myself in the end...

I needed the BOM option. The documentation states it should be set to true for UTF-8 files. But it defaults to false.

Excel by default generates csv files with BOM as the first character in CSV files. This gets picked up as part of the header (and key name) by the parser. With the bom option set to true, it can handle csv files generated from excel or other programs.

as your functions are async ones and they return a promises, you can do something like

You should actually be able to just pass both the fs-stream and the parser-stream to pipeline() and use your async iterator on the parser-stream:

It seems their documentation is incorrect. You need to require the npm module like this:

You have some issues with asynchronous call. I fixed your code, because only when an asynchronous function ends (i.e.: fileReader.onload) you can go on:

I think your problem is that the csv downloader is rendering with the current value of datas (which is null) before the fetch request is finished, and useRef does not cause a re-render, so its still using the null value even after the request is finished.

Switching datas to a state variable or adding a state variable to determine if that data has loaded

Here is an approach,

It looks like proper escaping for double quotes in csv is another double quote. So the line should be: