@toanerrors/async-middleware

Async middleware for Express

Table of Contents

• Introduction
• Installation
• Usage
• Configuration
• Examples
• Contributing
• License

Introduction

@toanerrors/async-middleware is a lightweight library that enhances Express applications with support for asynchronous middleware. This library wraps asynchronous request handlers to ensure that errors are properly passed to Express's error handling middleware.

Installation

You can install this library using npm:

npm install @toanerrors/async-middleware

or using yarn:

yarn add @toanerrors/async-middleware

or using bun:

bun add @toanerrors/async-middleware

Usage

To use @toanerrors/async-middleware, simply import the asyncMiddleware function and apply it to your Express application. This will enhance the specified HTTP methods to support asynchronous request handlers.

import express from "express";
import { asyncMiddleware } from "@toanerrors/async-middleware";

const app = express();

// Apply asyncMiddleware
asyncMiddleware(app);

// If you have routes that need to be enhanced with asyncMiddleware
const router = express.Router();
// Apply asyncMiddleware to the router
asyncMiddleware(router);

app.get("/", async (req, res) => {
  // Your asynchronous code here
  throw new Error("Something went wrong");
});

// Error-handling declare once
app.use((err, req, res, next) => {
  res.status(500).send(err.message);
});

app.listen(3000, () => {
  console.log("Server is running on port 3000");
});

using with express.Router

import express from "express";
import { asyncMiddleware } from "@toanerrors/async-middleware";

const router = express.Router();

asyncMiddleware(router);

router.get("/", async (req, res) => {
  // Your asynchronous code here
  throw new Error("Something went wrong");
});

// If you have already defined an error-handling function in the main file, you do not need to define it within the router.

export default router;

Configuration

The asyncMiddleware function accepts an optional configuration object that allows you to specify which HTTP methods should be enhanced with asynchronous support. By default, it supports the following methods: get, post, put, delete, and patch.

import express from "express";
import { asyncMiddleware } from "@toanerrors/async-middleware";

const app = express();
asyncMiddleware(app, {
  methods: ["get", "post"], // Only enhance GET and POST methods
});

app.get("/", async (req, res) => {
  res.send("Hello World");
});

app.post("/data", async (req, res) => {
  res.send("Data received");
});

app.use((err, req, res, next) => {
  res.status(500).send(err.message);
});

app.listen(3000, () => {
  console.log("Server is running on port 3000");
});

Examples

// file: index.ts
import express from "express";
import { asyncMiddleware } from "@toanerrors/async-middleware";
import router from "./router";

const app = express();
asyncMiddleware(app);

app.get("/error", async (req, res) => {
  throw new Error("Test error");
});

app.use("/router", router);

app.use((err, req, res, next) => {
  res.status(500).send(err.message);
});

app.listen(3000, () => {
  console.log("Server is running on port 3000");
});

// file: router.ts
import express from "express";
import { asyncMiddleware } from "@toanerrors/async-middleware";

const router = express.Router();

asyncMiddleware(router);

router.get("/error", async (req, res) => {
  throw new Error("Test error");
});

export default router;

Using with Multiple Handlers

import express from "express";
import { asyncMiddleware } from "@toanerrors/async-middleware";

const app = express();
asyncMiddleware(app);

const firstHandler = async (req, res, next) => {
  console.log("First handler");
  next();
};

const secondHandler = async (req, res) => {
  res.send("Second handler");
};

app.get("/", firstHandler, secondHandler);

app.use((err, req, res, next) => {
  res.status(500).send(err.message);
});

app.listen(3000, () => {
  console.log("Server is running on port 3000");
});

Contributing

Contributions are welcome! Please fork the repository and submit a pull request for any improvements or bug fixes.

License

MIT License Copyright (c) 2024 toanerrors