Express Native Promise Router

Motivation

Allows you to use async functions or return Promises in your route handlers.

This library wraps the express.Router and allows you to use its complete API.

Features

• Native promises
• Express standard API
• extend-ible class
• Lightweiget (0.7KB)

Installation

 $ npm install --save express-native-promise-router

or even better with yarn:

 $ yarn add express-native-promise-router

Usage

const express = require('express');
const PromiseRouter = require('express-native-promise-router');

const app = express();
const router = new PromiseRouter();

app.use(router);

router.get('/', (req, res) => {
  return Promise.resolve('demo');
});

app.use((req, res) => {
  res.end(res.locals.resolved);
});

Resolved state is being passed through res.locals.resolved because in most cases you'd like to wrap state and errors in your app's responses.

With async/await

const express = require('express');
const PromiseRouter = require('express-native-promise-router');

const app = express();
const router = new PromiseRouter();

app.use(router);

router.get('/', async (req, res) => {
  return await Promise.resolve('demo');
});

app.use((req, res) => {
  res.end(res.locals.resolved);
});

Comparison

Handling errors

By returning a promise rejections are automatically passed to next().

const router = new PromiseRouter();

app.use(router);

router.get('/users', (req, res) => {
  return db.collection('users').find({}).toArray();
});

app.use((error, req, res, next) => {
  res.status(500).json({ error });
});

app.use((req, res) => {
  res.json({ data: res.locals.resolved });
});

Using co

app.get('/users', (req, res, next) => co(function* () {
  res.locals.resolved = yield db.collection('users').find({}).toArray();
}).catch(next));

app.use((error, req, res, next) => {
  res.status(500).json({ error });
});

app.use((req, res) => {
  res.json({ data: res.locals.resolved });
});