https://github.com/zignis/deflight

Bypass express middlewares for pre-flight requests
https://github.com/zignis/deflight

express middleware preflight

Last synced: 10 days ago
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Bypass express middlewares for pre-flight requests

• Host: GitHub
• URL: https://github.com/zignis/deflight
• Owner: zignis
• License: mit
• Created: 2023-02-24T16:00:29.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-09-14T13:33:19.000Z (about 2 months ago)
• Last Synced: 2024-10-12T17:33:48.914Z (26 days ago)
• Topics: express, middleware, preflight
• Language: TypeScript
• Homepage: https://npmjs.com/package/deflight
• Size: 167 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 11
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

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README

        
# [De-flight](https://npmjs.com/package/deflight)



  

    

  

  

  

    

  



A middleware wrapper for [express](https://expressjs.com/) that skips calling the middleware for pre-flight requests.

## Installation

```shell

# Yarn

yarn add deflight

# NPM

npm install deflight

```

The package exports both a named and a default export:

```js

import { deflight } from "deflight";

// Or

import deflight from "deflight";

app.use(deflight(someMiddleware));

```

## When to use it?

If your app serves requests coming from a different origin than your server is hosted on, and you need to do something specifically with the pre-flight requests, for example, sending the `Access-Control-Allow-Methods` header on a per-route basis:

```js

app.use(deflight(someExpensiveMiddleware));

app.all('/example', (req, res, next) => {

  if ((req.method || '').toLowerCase() === 'options') {

    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');

    res.setHeader('Content-Length', '0');

    return res.status(204).end();

  }

  

  // Route logic

});

```

## Gotchas

### Using with the [CORS](https://expressjs.com/en/resources/middleware/cors.html) middleware

You need to enable the `preflightContinue` option to let the CORS middleware pass the pre-flight request

to subsequent middlewares and not return early.

```js

app.use(

  cors({

    origin: "https://example.com",

    preflightContinue: true, // Required

  })

);

```

### TypeScript

The wrapper uses the default `Request` type from the express package.

If you have extended the request object, or your middleware expects a different request object:

```ts

interface ExtendedRequest extends Request {

    customProp: string;

}

app.use(deflight(someMiddleware));

```

## License

Deflight is released under the [MIT License](./LICENSE).