AstralRinth/apps/frontend/src/middleware/auth.ts

const whitelistedParams = ['flow', 'error']

export default defineNuxtRouteMiddleware(async (_to, from) => {
	const config = useRuntimeConfig()
	const auth = await useAuth()

	if (auth.value.user) return

	const fullPath = from.fullPath

	const url = new URL(fullPath, config.public.apiBaseUrl)

	const extractedParams = Object.create(null) as Record<string, string>

	for (const param of whitelistedParams) {
		const val = url.searchParams.get(param)
		if (val != null) {
			extractedParams[param] = val
			url.searchParams.delete(param)
		}
	}

	return await navigateTo(
		{
			path: '/auth/sign-in',
			query: {
				redirect: `${url.pathname}${url.search}`,
				...extractedParams,
			},
		},
		{ replace: true },
	)
})