LocalKV is a simple, type-safe key-value data store to pass data or context between different parts of your application without propagating it through the whole application.
$ npm install localkvimport { randomUUID } from 'node:crypto';
import express from 'express';
import { KV } from 'localkv';
const app = express();
// create a new instance of KV
const kv = new KV();
// middleware to generate a new request id
app.use((req, res, next) => {
// generate new id for each request
const id = randomUUID();
console.log(`Request ID Generated: ${id}`);
// ^ "Request ID Generated: e4ce829d-7f67-453a-bc5a-a9db8e4edeef"
// create a new context for this request
kv.with(() => {
// set the request-id key to the generated id in this context
kv.set('request-id', id);
// execute the next middleware.
next();
});
});
app.get('/', (req, res) => {
// get the request-id from the context. Correct data will be automatically available without passing it through the whole application or mutating the request object.
const id = kv.get('request-id');
// send the id as response
res.json({ id });
});
app.listen(3000, () => {
console.log('Server is running on port 3000');
});$ curl http://localhost:3000
# {"id":"e4ce829d-7f67-453a-bc5a-a9db8e4edeef"}