express-convert

Convert express middleware to koa middleware
There is some difference between Express middleware and the converter, please see below.

Install

npm install express-convert

Usage

const convert = require('express-convert');
const Koa = require('koa');
const app = new Koa();
 
app.use(convert(expressMiddleware));

Express Compatibility

express-convert	express
@1	@4

Feature

Version	res.jsonp()	Custom JSON parser**
1.2.0	❌	❌
1.3.0	⭕️*	❌
1.3.1	✔️	❌
1.4.0	✔️	✔️

* does not support custom callback name
** the custom parser only applies on the res.jsonp() method because Koa will parse JSON for you in other cases.

Some differences

• req.app: req.app is a Koa app instance, not an Express app instance.
• Application Setting: The only setting implemented now is jsonp callback name for res.jsonp().
• req.cookies: Koa uses the cookies module so this property is not a parsed cookie object, for what it is, see Koa documents.
• req.params, req.app.METHOD() and req.route: Koa does not have router, so the properties is always undefined and the method always returns undefined and do nothing.
• req.signedCookies: this property is undefined, use req.cookies.get() with signed option.
• req.range(): Koa dones't support this, so this function always return undefined and do nothing.
• res.locals: Koa dones't support this, so this would be a empty object.
• res.cookie: Koa uses the cookie module to do the job, so the option is a little bit different, for more information, see Koa documents.
• res.clearCookie(): Koa does not support it, so this function will always return undefined and do nothing.
• res.download() and res.sendFile(): Koa does not support it, so this function will always return undefined and do nothing, consider use res.attach() to do file hosting job.
• res.end(): This generally does nothing because in Koa you do not need to end the response manually, just do nothing. Koa will end the response automatically.
• res.jsonp(): Koa does not have integrated support for this method, this is only a simple implementation. For better jsonp support, have a look at koa-jsonp.
• res.location() and res.links(): Koa does not have integrated support for them, but I plan to implement them in future versions, now they generally do nothing.
• res.render(): Koa does not support this, so it does nothing.