This is the first of a series of PRs, that let you pass functions, by
reference, to the client and back. E.g. through Server Context. It's
like client references but they're opaque on the client and resolved on
the server.
To do this, for security, you must opt-in to exposing these functions to
the client using the `"use server"` directive. The `"use client"`
directive lets you enter the client from the server. The `"use server"`
directive lets you enter the server from the client.
This works by tagging those functions as Server References. We could
potentially expand this to other non-serializable or stateful objects
too like classes.
This only implements server->server CJS imports and server->server ESM
imports. We really should add a loader to the webpack plug-in for
client->server imports too. I'll leave closures as an exercise for
integrators.
You can't "call" a client reference on the server, however, you can
"call" a server reference on the client. This invokes a callback on the
Flight client options called `callServer`. This lets a router implement
calling back to the server. Effectively creating an RPC. This is using
JSON for serializing those arguments but more utils coming from
client->server serialization.
This renames Module References to Client References, since they are in
the server->client direction.
I also changed the Proxies exposed from the `node-register` loader to
provide better error messages. Ideally, some of this should be
replicated in the ESM loader too but neither are the source of truth.
We'll replicate this in the static form in the Next.js loaders. cc
@huozhi @shuding
- All references are now functions so that when you call them on the
server, we can yield a better error message.
- References that are themselves already referring to an export name are
now proxies that error when you dot into them.
- `use(...)` can now be used on a client reference to unwrap it server
side and then pass a reference to the awaited value.
* Facebook -> Meta in copyright
rg --files | xargs sed -i 's#Copyright (c) Facebook, Inc. and its affiliates.#Copyright (c) Meta Platforms, Inc. and affiliates.#g'
* Manual tweaks
* Move files
* Update paths
* Rename import variables
* Rename /server to /writer
This is mainly because "React Server Server" is weird so we need another
dimension.
* Use "react-server" convention to enforce that writer is only loaded in a server
Sebastian Markbåge