@oazmi/build-tools
Version:
general deno build tool scripts which I practically use in all of my typescript repos
43 lines (42 loc) • 1.4 kB
JavaScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
import { DEFAULT_BUFFER_SIZE } from "./_constants.js";
/**
* Copies from `src` to `dst` until either EOF (`null`) is read from `src` or
* an error occurs. It resolves to the number of bytes copied or rejects with
* the first error encountered while copying.
*
* @example
* ```ts
* import { copy } from "@std/io/copy";
*
* const source = await Deno.open("my_file.txt");
* const bytesCopied1 = await copy(source, Deno.stdout);
* const destination = await Deno.create("my_file_2.txt");
* const bytesCopied2 = await copy(source, destination);
* ```
*
* @param src The source to copy from
* @param dst The destination to copy to
* @param options Can be used to tune size of the buffer. Default size is 32kB
*/
export async function copy(src, dst, options) {
let n = 0;
const bufSize = options?.bufSize ?? DEFAULT_BUFFER_SIZE;
const b = new Uint8Array(bufSize);
let gotEOF = false;
while (gotEOF === false) {
const result = await src.read(b);
if (result === null) {
gotEOF = true;
}
else {
let nwritten = 0;
while (nwritten < result) {
nwritten += await dst.write(b.subarray(nwritten, result));
}
n += nwritten;
}
}
return n;
}