'use client' Injection: Why Automated Migration Tools Need It (And When They Get It Wrong) (opens in new tab)

The Architectural Shift: From CSR to the App Router When moving from a Vite-based Single Page Application (SPA) to the Next.js App Router, the most significant mental hurdle isn't the file-system routing or the data fetching—it is the paradigm shift from "everything is a client component" to "Server Components by default." In a standard Vite project, your entire React tree is client-side. Every useState, useEffect, and event listener works everywhere because the whole bundle is shipped to the...