@thi.ng/file-io/file-chunks.js

Assorted file I/O utils (w/ logging support) for NodeJS/Bun

import { U32 } from "@thi.ng/hex";
import { open } from "node:fs/promises";
import { maskedPath } from "./mask.js";
async function* fileChunks(path, opts = {}) {
  let { size = 1024, start = 0, end = Infinity, logger } = opts;
  const mpath = maskedPath(path);
  logger?.debug(`start reading file chunks (size: 0x${size}):`, mpath);
  let fd = void 0;
  try {
    fd = await open(path, "r");
    while (start < end) {
      logger?.debug(
        `reading chunk: 0x${U32(start)} - 0x${U32(
          start + size - 1
        )} (${mpath})`
      );
      const { buffer, bytesRead } = await fd.read({
        buffer: Buffer.alloc(size),
        length: size,
        position: start
      });
      if (bytesRead === 0) break;
      yield buffer;
      if (bytesRead < size) break;
      start += bytesRead;
    }
  } finally {
    await fd?.close();
  }
}
export {
  fileChunks
};