Next.js · Client Components · Fresh / Intern · Concept
What does the `'use client'` directive mean?
Short Interview Answer
It marks a module and its transitive imports as part of the client bundle boundary.
Detailed Explanation
The file becomes a Client Component entry. Children imported into it are also client-side unless they are server-imported separately above the boundary. It does not mean 'only runs on client' — Client Components still SSR/hydrate.