Stream Not Closed (ARCH3081)

Key typescript.performance.stream-not-closed · Severity error · Category performance

Opening a file stream or reader/writer without closing it leaks OS handles and eventually causes handle exhaustion.

Incorrect

async function read(path: string): Promise<string> {
  const stream = fs.createReadStream(path);
  return await readAll(stream);
  // stream is never closed
}

Correct

async function read(path: string): Promise<string> {
  const stream = fs.createReadStream(path);
  try {
    return await readAll(stream);
  } finally {
    stream.close();
  }
}

Fix

Close streams with try/finally or using so handles are released on every path.