How to use the ref-napi.get function in ref-napi

// Get a "handle" of the active window
  const activeWindowHandle = user32.GetForegroundWindow();

  if (isNull(activeWindowHandle)) {
    return undefined; // Failed to get active window handle
  }

  // Get memory address of the window handle as the "window ID"
  const windowId = address(activeWindowHandle);

  // Allocate a buffer to store the process ID
  const processIdBuffer = alloc('uint32');
  // Write the process ID creating the window to the buffer (it returns the thread ID, but it's not used here)
  user32.GetWindowThreadProcessId(activeWindowHandle, processIdBuffer);
  // Get the process ID as a number from the buffer
  const processId = get(processIdBuffer);

  // Create a new instance of Rect, the struct required by the `GetWindowRect` method
  const bounds = new Rect();
  // Get the window bounds and save it into the `bounds` variable
  const getWindowRectResult = user32.GetWindowRect(activeWindowHandle, bounds.ref());

  if (getWindowRectResult === 0) {
    return undefined; // Failed to get window rect
  }

  return {
    platform: 'windows',
    id: windowId,
    owner: {
      processId,
    },

// This assumes using the "Basic Multilingual Plane" of Unicode, only 2 characters per Unicode code point
	// Include some extra bytes for possible null characters
	const windowTextBuffer = Buffer.alloc((windowTextLength * 2) + 4);
	// Write the window text to the buffer (it returns the text size, but it's not used here)
	user32.GetWindowTextW(activeWindowHandle, windowTextBuffer, windowTextLength + 2);
	// Remove trailing null characters
	const windowTextBufferClean = ref.reinterpretUntilZeros(windowTextBuffer, wchar.size);
	// The text as a JavaScript string
	const windowTitle = wchar.toString(windowTextBufferClean);

	// Allocate a buffer to store the process ID
	const processIdBuffer = ref.alloc('uint32');
	// Write the process ID creating the window to the buffer (it returns the thread ID, but it's not used here)
	user32.GetWindowThreadProcessId(activeWindowHandle, processIdBuffer);
	// Get the process ID as a number from the buffer
	const processId = ref.get(processIdBuffer);
	// Get a "handle" of the process
	const processHandle = kernel32.OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, false, processId);

	if (ref.isNull(processHandle)) {
		return undefined; // Failed to get process handle
	}

	// Set the path length to more than the Windows extended-length MAX_PATH length
	const pathLengthBytes = 66000;
	// Path length in "characters"
	const pathLengthChars = Math.floor(pathLengthBytes / 2);
	// Allocate a buffer to store the path of the process
	const processFileNameBuffer = Buffer.alloc(pathLengthBytes);
	// Create a buffer containing the allocated size for the path, as a buffer as it must be writable
	const processFileNameSizeBuffer = ref.alloc('uint32', pathLengthChars);
	// Write process file path to buffer

exports.MQDLH.getHeader = function(buf) {
  var jsdlh = new exports.MQDLH();
  _copyDLHfromC(ref.get(buf,0,_MQDLHffi_t),jsdlh);
  return jsdlh;
};

exports.MQRFH2.getHeader = function(buf) {
  var jsRFH2 = new exports.MQRFH2();
  _copyRFH2fromC(ref.get(buf,0,_MQRFH2ffi_t),jsRFH2);
  return jsRFH2;
};