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"use server"

Perform actions on the server environment only (i.e. console logging, etc.).

tsx
const logHello = async (message: string) => {
  "use server";
  console.log(message);
};
tsx
const logHello = async (message: string) => {
  "use server";
  console.log(message);
};

Usage

Basic usage

To create a function that only runs on the server, insert "use server" directive at the top of the function.

tsx
const logHello = async (message: string) => {
  "use server";
  console.log(message);
};
 
logHello("Hello");
tsx
const logHello = async (message: string) => {
  "use server";
  console.log(message);
};
 
logHello("Hello");

In this example, regardless of whether we are rendering this on the server or in the browser, the logHello function generates a log on the server console only. How does it work? We use compilation to transform the use server function into an RPC call to the server.

Serialization

Server functions allow the serialization of many different data types in the response. The full list is available here.

Meta information

Depending on your hosting, the server function might be running in parallel on multiple cpu cores or workers. You can use getServerFunctionMeta to retrieve a function-specific id, which is stable across all instances.

Keep in mind: this id can and will change between builds!

tsx
import { getServerFunctionMeta } from "@solidjs/start/server";
 
// or some in-memory db
const appCache: any = globalThis;
 
const counter = async () => {
  "use server";
  const { id } = getServerFunctionMeta()!;
  const key = `counter_${id}`;
  appCache[key] = appCache[key] ?? 0;
  appCache[key]++;
 
  return appCache[key] as number;
};
tsx
import { getServerFunctionMeta } from "@solidjs/start/server";
 
// or some in-memory db
const appCache: any = globalThis;
 
const counter = async () => {
  "use server";
  const { id } = getServerFunctionMeta()!;
  const key = `counter_${id}`;
  appCache[key] = appCache[key] ?? 0;
  appCache[key]++;
 
  return appCache[key] as number;
};