lifecyclemigrate-from-nextjslisted

# Migrate from Next.js App Router to TanStack Start This is a step-by-step migration checklist. Complete tasks in order. > **CRITICAL**: TanStack Start is isomorphic by default. ALL code runs in both environments unless you use `createServerFn`. This is the opposite of Next.js Server Components, where code is server-only by default. > **CRITICAL**: TanStack Start uses `createServerFn`, NOT `"use server"` directives. Do not carry over any `"use server"` or `"use client"` directives. > **CRITICAL**: Types are FULLY INFERRED in TanStack Router/Start. Never cast, never annotate inferred values. ## Pre-Migration - [ ] **Create a migration branch** ```bash git checkout -b migrate-to-tanstack-start ``` - [ ] **Install TanStack Start** ```bash npm i @tanstack/react-start @tanstack/react-router npm i -D vite @vitejs/plugin-react ``` - [ ] **Remove Next.js** ```bash npm uninstall next @next/font @next/image ``` ## Concept Mapping | Next.js App Router | TanStack Start | | -------------------------------- | ------------------------------------------------------------------------- | | `app/page.tsx` | `src/routes/index.tsx` | | `app/layout.tsx` | `src/routes/__root.tsx` | | `app/posts/[id]/page.tsx` | `src/routes/posts/$postId.tsx`