How to submit a form with KotlinJS and React? - reactjs

Question

I want to display a file selector and a submit button.
The file is only to be submitted once the button is clicked.
The submit/action target is on another server though.
I looked at react examples, but I can't figure out the exact method on how to
realise this with KotlinJS and React.
The duplicates in formMethod and onSubmitFunction are just me trying and seeing what sticks.
I also tried adding method = FormMethod.post, encType = FormEncType.multipartFormData directly to the form, but it didn't help. It doesn't even output the debug print.
EDIT: I do not need to do something with the file otherwise and want to leverage the default form functionality for the upload. The other server is also mine and has a simple html/http upload where this suffices:
<form method="post" enctype="multipart/form-data">
<input type="file" name="file">
<input type="submit" value="Upload">
</form>
ENDEDIT
EDIT2: I changed the code a little and now it refers to the other server, but does not append any files.
private fun RBuilder.render() {
form(
method = FormMethod.post,
encType = FormEncType.multipartFormData,
action = "https://otherserver.com/upload"
) {
styledInput {
attrs {
type = InputType.file
accept = ".zip"
multiple = false
}
}
styledInput {
attrs {
type = InputType.submit
value = "Test"
}
}
}
}

Answer 1

It seems like in this case the name parameter is strictly required.
The following works:
private fun RBuilder.render() {
form(
method = FormMethod.post,
encType = FormEncType.multipartFormData,
action = "https://otherserver.com/upload"
) {
styledInput {
attrs {
name = "upload"
type = InputType.file
accept = ".zip"
multiple = false
}
}
styledInput {
attrs {
type = InputType.submit
value = "Test"
}
}
}
}