std/encoding/csv.ts - parse and stringify should not require async code when data is already in memory

[dsherret]

Right now, the code in https://github.com/denoland/deno/blob/std/0.82.0/std/encoding/csv.ts forces the caller of parse and stringify to await the result, but there is no reason for these functions to be async when the object is already in memory.

[lowlighter]

All async code requirement seems to come from this single line:
https://github.com/denoland/deno_std/blob/3931030e7fae16158e3b6cb041a2a161c0cba6e3/encoding/csv.ts#L262

And from the function signature, it seems both string and BufReader are supported:
https://github.com/denoland/deno_std/blob/3931030e7fae16158e3b6cb041a2a161c0cba6e3/encoding/csv.ts#L392-L393

Not sure why we actually support BufReader (maybe because it was ported from Go?) but I think we should drop the support for it. With only strings as input it would be easier to make it synchronous.

YAML/TOML (and native JSON) libs only support strings as input so it would actually be more consistent

PS: seems you linked an old version of std (0.82.0 v 0.95.0) though it's still revelant as of today

[MierenManz]

I want to pick up this issue. It seems like I only have the remove the BufReader input and the code related to that? I hope I understood that correctly tho

[MierenManz]

Anyone else can try if they want.
I don't got the time to pick up this issue.

[kt3k]

(Sorry for the late reply, but) I think async parse (with BufReader) might make sense if the source csv file is very big. That should reduce the memory usage and execution time.

[luk3skyw4lker]

I could take a look on that too, I'm already on the works of another issue envolving the same file. I'm just not sure if this is already solved.

[lino-levan]

@kt3k This issue should probably be closed. std/encoding/csv.ts is no longer async and it also no longer supports BufReader.

Sanity check: https://deno.land/std@0.168.0/encoding/csv.ts?doc=&s=parse

[kt3k]

@lino-levan Thanks for the ping. Right, both are now sync. This issue should be now closed.

refs:

• parse became sync in feat(encoding/csv): sync parse #2491
• stringify became sync in feat(encoding/csv): sync stringify function  #2611