Docs: missing documentation for react compiler "compilationMode: annotation"

[Chenalejandro]

What is the documentation issue?

How does the annotation works?

In the react website there is the use no memo directive (https://react.dev/learn/react-compiler#something-is-not-working-after-compilation), but I am not sure if the annotation mode is refering that.

From my testing, "use no memo" works by just setting this:

  experimental: {
    reactCompiler: true,
  },

The annotation mode in next.js makes me think that it is more an opt-in feature than the use no memo's opt-out.

Is there any context that might help us understand?

No

Does the docs page already exist? Please link to it.

https://nextjs.org/docs/canary/app/api-reference/next-config-js/reactCompiler

[Chenalejandro]

Just found the annotation mode in the react 19 docs: https://19.react.dev/learn/react-compiler. So, to opt-in we should use the use memo directive.

[liby]

I'd like to clarify my understanding of the compilationMode: 'annotation' mode:

When using compilationMode: 'annotation', components are NOT optimized by default, and only components that explicitly use the "use memo" directive will be optimized by the compiler?

This would make it an opt-in approach, as opposed to the default mode (reactCompiler: true) which optimizes all components by default and allows opting out with "use no memo".

Is this understanding correct?

[amarpatel]

I've confirmed your understanding as correct on my local env 👍