function isWriter(it: unknown): it is Writer;

Checks if a given value is an asynchronous Writer, which is an object that implements a write method as per Deno's Writer interface.

true if the value is an asynchronous Writer, false otherwise.

I/O

import { isWriter } from "jsr:@nick/is/writer";

isWriter(Deno.stdout); // true
isWriter(Deno.stderr); // true
isWriter(Deno.stdin); // false

An abstract interface which when implemented provides an interface to write bytes from an array buffer to a file/resource asynchronously.

I/O

write(
    p: Uint8Array,
  ): Promise<number>;

Writes p.byteLength bytes from p to the underlying data stream. It resolves to the number of bytes written from p (0 <= n <= p.byteLength) or reject with the error encountered that caused the write to stop early. write() must reject with a non-null error if would resolve to n < p.byteLength. write() must not modify the slice data, even temporarily.

This function is one of the lowest level APIs and most users should not work with this directly, but rather use writeAll() from std/streams/write_all.ts instead.

Implementations should not retain a reference to p.