@xcvzmoon/express-utils

A collection of utilities for Express. More will be added over time.

Current utilities

Request validation with Zod:

• readValidatedBody — validate and type req.body with a Zod schema
• readValidatedParams — validate and type req.params with a Zod schema
• readValidatedQuery — validate and type req.query with a Zod schema

Multipart form data:

• readMultipartFormData — parse multipart/form-data and get uploaded files as { name, filename, mimeType, buffer }[], or null if the request is not multipart (uses busboy)

Server-Sent Events (SSE):

• createServerSentEvent — set up an Express response for SSE and get { push, pushComment, close, closed } to send events, comments, and close the connection

Install

bun add @xcvzmoon/express-utils express zod
# or
npm i @xcvzmoon/express-utils express zod

Usage

Zod validation:

import {
  readValidatedBody,
  readValidatedParams,
  readValidatedQuery,
} from '@xcvzmoon/express-utils';
import { z } from 'zod';

const bodySchema = z.object({ name: z.string() });
const paramsSchema = z.object({ id: z.string() });
const querySchema = z.object({ page: z.coerce.number().optional() });

app.post('/users/:id', (req, res) => {
  const body = readValidatedBody(req, bodySchema);
  const params = readValidatedParams(req, paramsSchema);
  const query = readValidatedQuery(req, querySchema);
  // body, params, query are typed and validated
});

Multipart form data:

import { readMultipartFormData } from '@xcvzmoon/express-utils';

app.post('/upload', async (req, res) => {
  const files = await readMultipartFormData(req);
  if (files === null) return res.status(400).send('Expected multipart/form-data');
  for (const { name, filename, mimeType, buffer } of files) {
    // handle each uploaded file
  }
});

Server-Sent Events:

import { createServerSentEvent } from '@xcvzmoon/express-utils';

app.get('/events', (req, res) => {
  const sse = createServerSentEvent(res);

  sse.push('data: Connected\n\n');

  const heartbeat = setInterval(() => sse.pushComment('heartbeat'), 10000);

  req.on('close', () => {
    clearInterval(heartbeat);
    sse.close();
  });
});

Peer dependencies

• express ^5.2.1
• zod ^4.3.6