Ryan Florence released this a few months ago:
A lightweight, type-safe async context management system for JavaScript applications. Perfect for server-side applications where you need to share request-scoped values across components and functions.
This is a small wrapper on top of AsyncLocalStorage to provide a simple and type-safe API for request scoped values.
This is expected to be the recommended solution for type-safe context in upcoming React Router middleware.
import { createContext, provide, pull } from "@ryanflorence/async-provider";
// 1. ✅ Create your contexts
let userContext = createContext<User>();
let dbContext = createContext<Database>();
async function myHandleRequest(req: Request) {
// setup context values
let user = await myAuthenticateUser(req);
let db = myCreateDatabaseConnection(user);
// 2. ✅ Provide contexts
let html = await provide(
new Map([
[userContext, user],
[dbContext, db],
]),
async () => {
// run your app code within this context
let result = await renderApp();
// Can return values from provider callback
return result;
},
);
return new Response(html, {
headers: { "Content-Type": "text/html" },
});
}
// 3. ✅ Pull context from anywhere
function renderApp() {
let user = pull(userContext);
let db = pull(dbContext);
// Use user and db...
}
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