@awaitjs/express

@awaitjs/express

Write Express middleware and route handlers using async/await

Usage

const { addAsync } = require('@awaitjs/express');

// Or, if you want to use `wrap()`
const { wrap } = require('@awaitjs/express');

API

addAsync()

The addAsync() function is the preferred way to add async/await support to your Express app. This function adds several helper functions to your Express app.

It adds useAsync(), getAsync(), etc. to your Express app

The addAsync() function adds useAsync(), deleteAsync(), getAsync(), headAsync(), paramAsync(), patchAsync(), postAsync(), and putAsync().

const express = require('express');
const app = addAsync(express());

// `useAsync()` is like `app.use()`, but supports async functions
app.useAsync(async function(req, res, next) {
  await new Promise(resolve => setTimeout(resolve, 50));
});

// `getAsync()` is like `app.get()`, but supports async functions
app.getAsync('*', async function(req, res, next) {
  throw new Error('Oops!');
});

// Because of `getAsync()`, this error handling middleware will run.
// `addAsync()` also enables async error handling middleware.
app.use(function(error, req, res, next) {
  res.send(error.message);
});

const server = await app.listen(3000);

Router()

This module exports a Router() function that is a drop-in replacement for express.Router(), except the returned router has getAsync(), useAsync(), etc.

It exports a Router function that returns a new async-friendly router

const express = require('express');
const app = express(); // This app isn't async friendly.

const router = Router(); // But this router is.
router.getAsync('/foo', async function(req, res, next) {
  throw new Error('Oops!');
});

app.use(router);
app.use(function(err, req, res, next) {
  res.send(err.message);
});

const server = await app.listen(3000);

decorateApp

acquit:ignore:end

It is an alias for addAsync()

assert.equal(decorateApp, addAsync)

decorateRouter

It is an alias for addAsync()

assert.equal(decorateRouter, addAsync)

wrap()

If you need more fine-grained control than what addAsync() gives you, you can use the wrap() function. This function wraps an async Express middleware or route handler for better error handling.

It wraps an async function with Express-compatible error handling

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

// `wrap()` takes an async middleware or route handler and adds a
// `.catch()` to handle any errors. It also prevents double-calling
// `next()`.
app.get('*', wrap(async function(req, res, next) {
  throw new Error('Oops!');
}));

// `wrap()` also supports async error handling middleware.
app.use(wrap(async function(error, req, res, next) {
  throw new Error('foo');
}));

app.use(function(error, req, res, next) {
  res.send(error.message); // Will send back 'foo'
});

const server = await app.listen(3000);