ssr flag is ignored in react-router v7

[igortas]

Hi,

Why react-router starting in SSR mode, besides the flag is set to false in react-router.config.ts.

import type { Config } from '@react-router/dev/config';

export default {
    appDirectory: 'src',
    ssr: false
} satisfies Config;

I'm getting:

[vite] Internal server error: window is not defined

I'm using pnpm v9.13.2
Node is on version 23.3.0
React 18.3

[heikkilamarko]

Hi. We faced these errors as well with the same configuration when migrating to v7. To resolve this, we moved all the window-related code, such as localStorage calls, into functions invoked by clientLoader and clientActions.

Our app is a PWA that uses Vite PWA. It seems that @react-router/dev does not work well with it, so we decided not to use it and instead followed our existing approach (createBrowserRouter + RouterProvider) documented here: React Router: Custom Framework Integration

Based on my initial impression, the new Framework approach may not be the best choice for building a pure SPA or PWA, particularly if you don't intend to use SSR in the future. The Custom Framework approach feels more straightforward and less limiting.

[igortas]

@heikkilamarko My idea was go upgrade our codebase with client loaders, to clean a bit some components, and definetly make the app SSR ready after that. Thanks I'll try to experiment with the link u provide me, I've ommited in the docs.

[leonardbiofi]

Same issue on my side. I had just migrated from react-router v6 to react router v7 using the framwork approach.

However my component that were supposed to be only client renderer are failing because of that. I have set the ssr flag to false but it does not work.

Any idea ?

[igortas]

@leonardbiofi I've set the ssr flag in vite, I had some imports that were making problem. Looks like RR is running in server mode when app is starting...

	ssr: {
		optimizeDeps: ['lodash', 'exceljs', '@mui/*'],
		noExternal: ['lodash', 'exceljs', '@mui/*']
	},

[leonardbiofi]

I think I will not adopt the framework mode before all of this get more stable. Anyway I am currently using a Auth SPA, so server side rendering is not really advantageous to me. I just wanted to leverage the automatic bundling per routes which I think was a nice feature. I'll wait a bit longer that all this gets less experimental.