import fs from 'node:fs';
import { StreamReader } from 'peek-readable';

(async () => {
  const readable = fs.createReadStream('JPEG_example_JPG_RIP_001.jpg');
  const streamReader = new StreamReader(readable);
  const uint8Array = new Uint8Array(16);
  const bytesRead = await streamReader.read(uint8Array, 0, 16);;
  // buffer contains 16 bytes, if the end-of-stream has not been reached
})();

(async () => {

  const fileReadStream = fs.createReadStream('JPEG_example_JPG_RIP_001.jpg');
  const streamReader = new StreamReader(fileReadStream);
  const buffer = Buffer.alloc(16); // or use: new Uint8Array(16);

  try {
    await streamReader.read(buffer, 0, 16);
    // buffer contains 16 bytes, if the end-of-stream has not been reached
  } catch(error) {
    if (error instanceof EndOfStreamError) {
      console.log('End-of-stream reached');
    }
  }
})();

import fs from 'node:fs';
import { StreamReader } from 'peek-readable';

const fileReadStream = fs.createReadStream('JPEG_example_JPG_RIP_001.jpg');
const streamReader = new StreamReader(fileReadStream);
const buffer = Buffer.alloc(20);

(async () => {
  let bytesRead = await streamReader.peek(buffer, 0, 3);
  if (bytesRead === 3 && buffer[0] === 0xFF && buffer[1] === 0xD8 && buffer[2] === 0xFF) {
    console.log('This is a JPEG file');
  } else {
    throw Error('Expected a JPEG file');
  }

  bytesRead = await streamReader.read(buffer, 0, 20); // Read JPEG header
  if (bytesRead === 20) {
    console.log('Got the JPEG header');
  } else {
    throw Error('Failed to read JPEG header');
  }
})();