Function randomFill

lib/internal/crypto/random.js:154–196

(buf, offset, size, callback)

}

function randomFill(buf, offset, size, callback) {
  if (!isAnyArrayBuffer(buf) && !isArrayBufferView(buf)) {
    throw new ERR_INVALID_ARG_TYPE(
      'buf',
      ['ArrayBuffer', 'ArrayBufferView'],
      buf);
  }

  const elementSize = buf.BYTES_PER_ELEMENT || 1;

  if (typeof offset === 'function') {
    callback = offset;
    offset = 0;
    // Size is a length here, assertSize() call turns it into a number of bytes
    size = buf.length;
  } else if (typeof size === 'function') {
    callback = size;
    size = buf.length - offset;
  } else {
    validateFunction(callback, 'callback');
  }

  offset = assertOffset(offset, elementSize, buf.byteLength);

  if (size === undefined) {
    size = buf.byteLength - offset;
  } else {
    size = assertSize(size, elementSize, offset, buf.byteLength);
  }

  if (size === 0) {
    callback(null, buf);
    return;
  }

  const job = new RandomBytesJob(
    kCryptoJobAsync,
    buf,
    offset,
    size);
  job.ondone = FunctionPrototypeBind(onJobDone, job, buf, callback);
  job.run();
}

// Largest integer we can read from a buffer.
// e.g.: Buffer.from("ff".repeat(6), "hex").readUIntBE(0, 6);