is there a way to pass a suspend function instead ...

# javascript

[Alex Styl]

is there a way to pass a suspend function instead of a regular function into an external object's function parameters?

I am using express js from kotlinjs like this

external object Express {
    fun get(path: String, handler: (req: dynamic, res: dynamic) -> Unit)
}

And I would like to do

express.get("/") {
    // suspend here ?
}

similar to how in normal js i would just add async into the function like this:

app.get('/', async (req, res) => {
    // I can use await here
})

[Alex Styl]

I tried just marking the handler as a suspend function but express throws saying hander is not a function

[jw]

the function returns a promise so instead of { suspend code here } do { GlobalScope.async { suspend code here } }

[jw]

you might have to asPromise() that. been a few years since i've done anything with promises

[Alex Styl]

my bad. the return type is wrong while experimenting with something. it should in fact be -> Unit. (i edited my snippet)

my question is specific to how do I pass async functions similar to how i would do in js

I already launch my own coroutine as a workaround from within the handler. would love to know if this is supported by kotlin/js instead

[jw]

No

[jw]

If it's a regular function you only get to run synchronous code or schedule on the event loop

[turansky]

If async handler supported by express - then signature is invalid and it must be Promise<Void>? instead of Unit

[Alex Styl]

@turansky it doesn't. the real signature in js is:

export type RequestParamHandler = (req: Request, res: Response, next: NextFunction, value: any, name: string) => any;

in normal js i use async so that i get to use await inside the callback, but express doesnt really use the promise

[turansky]

Fastify?

[turansky]

As I see - it supports async handlers

[Alex Styl]

i'm not interested in changing frameworks. i can figure out the syntax i want (ie adding some extension function). my question was about whether it is possible or not, and it seems like it is not

[turansky]

Do you write declarations for express yourself?

[Alex Styl]

yup