BREAKING(io): remove copyN()

[iuioiua]

What's changed

copyN() has been removed from @std/io.

Motivation

This change was made to help push users towards using the Streams API and @std/streams, and make design decisions about which APIs easier.

Migration guide

To migrate, use ByteSliceStream, setting start to 0 and end to 1 less than that of size in concatN(), then pipe to the destination writable stream.

- import { copyN } from "@std/io/copy-n";
+ import { ByteSliceStream } from "@std/streams/byte-slice-stream";

  const source = await Deno.open("README.md");

- await copyN(source, Deno.stdout, 10);
+ await source.readable
+   .pipeThrough(new ByteSliceStream(0, 9))
+   .pipeTo(Deno.stdout.writable);

Related

Towards #5989

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.29%. Comparing base (05b6d7e) to head (3703431).
Report is 41 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5999   +/-   ##
=======================================
  Coverage   96.29%   96.29%           
=======================================
  Files         493      492    -1     
  Lines       39530    39497   -33     
  Branches     5833     5828    -5     
=======================================
- Hits        38065    38035   -30     
+ Misses       1423     1420    -3     
  Partials       42       42           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[kt3k]

LGTM

[kt3k]

The user might need ReadableStreamBYOBReader#read for the replacement if they need more accurate translation. readable.pipeThrough(new ByteSliceStream(0, 9)) consumes the entire readable stream, while copyN doesn't consume the entire reader. (The reader is paused at the end of copied bytes, and can be resumed from there)