A way to use async/await in Express routes

async-router.js

const express = require('express');
const methods = require('methods');

function AsyncRouter(options) {
  const router = express.Router(options);
  Object.setPrototypeOf(router, AsyncRouter.prototype);
  return router;
}

Object.setPrototypeOf(AsyncRouter.prototype, express.Router);

const catchAsyncError = fn => (req, res, next) => Promise.resolve(fn(req, res, next)).catch(next);

for (const method of methods.concat('all')) {
  AsyncRouter.prototype[method] = function (path, ...fns) {
    return express.Router[method].call(this, path, ...fns.map(catchAsyncError));
  }
}

AsyncRouter.prototype.use = function (pathOrFn, ...fns) {
  const wrappedPathOrFn = typeof path === 'function' ? catchAsyncError(path) : path;
  return express.Router.use.call(this, wrappedPathOrFn, ...fns.map(catchAsyncError));
}

module.exports = AsyncRouter;

test.js

const AsyncRouter = require('./async-router');
const express = require('express');

const routes = new AsyncRouter();

routes.get('/', async (req, res) => {
  res.send(await Promise.resolve('hello world'));
});

const app = express();
app.use(routes);
app.listen(3000);

console.error('listening on http://localhost:3000');