jgraph/drawio-desktop · error · Error

bad arg: fileObject

Error message

bad arg: fileObject

What it means

In the rendererReq switch (src/main/electron.js:3840-3844), the 'saveFile' case throws 'bad arg: fileObject' when args.fileObject is null/undefined before reqStr validates fileObject.path. This is the IPC entry guard for saveFile.

Source

Thrown at src/main/electron.js:3841

			fonts = [...new Set(fonts)].sort(
				(a, b) => a.localeCompare(b));
			resolve(fonts);
		});
	});
}

ipcMain.on("rendererReq", async (event, args) =>
{
	if (!validateSender(event.senderFrame)) return null;

	try
	{
		let ret = null;

		switch(args.action)
		{
		case 'saveFile':
			if (args.fileObject == null) throw new Error('bad arg: fileObject');
			reqStr(args.fileObject.path, 'fileObject.path');
			ret = await saveFile(args.fileObject, args.data, args.origStat, args.overwrite, args.defEnc);
			break;
		case 'writeFile':
			reqStr(args.path, 'path');
			ret = await writeFile(args.path, args.data, args.enc);
			break;
		case 'saveDraft':
			if (args.fileObject == null) throw new Error('bad arg: fileObject');
			reqStr(args.fileObject.path, 'fileObject.path');
			ret = await saveDraft(args.fileObject, args.data);
			break;
		case 'getFileDrafts':
			if (args.fileObject == null) throw new Error('bad arg: fileObject');
			reqStr(args.fileObject.path, 'fileObject.path');
			ret = await getFileDrafts(args.fileObject);
			break;
		case 'getBkpFile':

View on GitHub (pinned to 403a2cb79f)

Solutions

1. Ensure the renderer constructs a fileObject ({path, encoding?}) before dispatching saveFile.
2. Gate the save button/menu on fileObject presence.
3. Log args at dispatch to confirm fileObject was set.

Example fix

// before
if (xml) electron.request({action: 'saveFile', fileObject: currentFile, data: xml});

// after
if (xml && currentFile && currentFile.path) {
  electron.request({action: 'saveFile', fileObject: currentFile, data: xml});
}

const hasFileObject = (args) => args && args.fileObject != null && typeof args.fileObject === 'object';
if (!hasFileObject(args)) throw new TypeError('fileObject required');

function hasFileObject(args) {
	return args != null && args.fileObject != null && typeof args.fileObject === 'object';
}

try { await electron.request({action: 'saveFile', fileObject, data}); }
catch (e) {
	if (e.message === 'bad arg: fileObject') { /* prompt user to Save As first */ return; }
	throw e;
}

When it happens

Trigger: Renderer sends {action: 'saveFile', fileObject: null, data} or omits fileObject entirely.

Common situations: Save triggered before a file was opened/created (no fileObject yet); a refactor dropped the fileObject from the payload; structured-clone dropped a non-cloneable fileObject.

Related errors

• bad arg: ${name}
• bad arg: fileObject.path
• path not authorised
• Invalid file data
• all saving trials failed

AI-assisted analysis of jgraph/drawio-desktop@403a2cb79f (2026-08-13). Data as JSON: /api/errors/662ad26dae7712c9. Report an issue: GitHub.