https://github.com/vkurchatkin/koa-connect

Use connect and express middleware in koa
https://github.com/vkurchatkin/koa-connect

Last synced: 3 days ago
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Use connect and express middleware in koa

• Host: GitHub
• URL: https://github.com/vkurchatkin/koa-connect
• Owner: vkurchatkin
• License: mit
• Created: 2014-08-19T15:54:54.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2023-03-03T16:53:19.000Z (almost 2 years ago)
• Last Synced: 2025-01-17T23:14:28.327Z (10 days ago)
• Language: TypeScript
• Size: 167 KB
• Stars: 169
• Watchers: 3
• Forks: 25
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-koa - koa-connect - 在Koa中使用connect和express中间件。   (仓库 / 中间件)

README

        
# koa-connect [![npm package badge][npm badge]][npm]

[npm badge]: https://badge.fury.io/js/koa-connect.svg

[npm]: https://www.npmjs.com/package/koa-connect

Use [Express](https://github.com/strongloop/express)/[Connect](https://github.com/senchalabs/connect) middleware with [Koa](https://github.com/koajs/koa).

## Warning

It is **highly** recommended to use a Koa-specific middleware instead of trying to convert an Express version when they're available. There is a non-trivial difference in the Koa and Express designs and you will inevitably run into some issues. This module is a workaround for the specific cases where the differences can be ignored. Additionally, it also enables library authors to write 1 version of their HTTP middleware.

### Always use `next` middleware parameter

Express middlewares need to declare and invoke the `next` callback appropriately for the koa-connect integration to work correctly.

### For library authors

If you're attempting to write a framework-agnostic middleware library, be sure to use only core HTTP methods and not any Express-dependent APIs like `res.send`.

## Installation

```sh

npm install koa-connect

```

## Usage

See [`examples/`](./examples) for more practical usage.

```javascript

const Koa = require('koa');

const c2k = require('koa-connect');

// A generic Express-style middleware function

function connectMiddlware(req, res, next) {

  res.writeHead(200, { 'Content-Type': 'text/plain' });

  res.end('From the Connect middleware');

  next();

}

// A generic Koa middlware, without async/await

function koaMiddlware(ctx, next) {

  next()

    .then(() => {

      // The control flow will bubble back to here, like usual

    })

    .catch((err) => {

      // Error handling from downstream middleware, like usual

    });

}

// A generic Koa middlware with async/await

async function koaMiddleware(ctx, next) {

  try {

    await next();

  } catch (e) {

    // Normal error handling

  }

  // Normal control flow

}

const app = new Koa();

app.use(koaMiddlware);

app.use(c2k(connectMiddlware));

app.use((ctx, next) => {

  console.log('It will continue on to here');

});

app.listen(3000);

```

## Contributing

### Developing

`npm start` starts the TypeScript compiler in watch mode. Code will be auto-formatted upon commit as part of the Prettier + lint-staged + Husky setup.

### Building

`npm run build` produces the types declaration file and JavaScript file for publishing.

### Testing

`npm test` runs the tests. Tests are in `tests.js` and are made with the [Mocha](https://mochajs.org) framework.

Use `npm run test:watch` in conjunction with `npm start` to automatically re-run the tests when the source changes.

## License

MIT