React Typescript onSubmit type

Question

I'm having issues around creating an onSubmit function and giving it a type.

On the very first line where you'd normally set a type for the function, no matter what I seem to give even any or unknown I'm seeing an error.

The error suggests I can't put type of any on the type of

(event: FormEvent<HTMLFormElement>, data: FormProps) => void

But even if I do give it this exact suggested type I still return an error.

const onSubmitHandler = (
e: SyntheticEvent<HTMLFormElement>,
setVerificationId: Dispatch<SetStateAction<string>>, 
setVerificationToken: Dispatch<SetStateAction<VerificationStatus>>): TRYING_TO_RESOLVE_WHAT_THIS_TYPE_IS => {
        e.preventDefault()
        setUserData({
            platform: '',
            name: {
                givenNames: givenNames ? givenNames : memberDetails.memberNameDetails.givenNames,
                surname: surname ? surname : memberDetails.memberNameDetails.lastName
            },
            email: email,
            dob: formattedDateOfBirth,
            currentAddress: {
                line1: streetNameInformation,
                postCode: postCode,
                suburb: suburb,
                state: state,
                country: country,
            }})

        aService.postVerificationRegister(userData)
            .then(response => {
                setVerificationId(response.verificationId)
                setVerificationToken(response.verificationToken)
            })
            .catch((e) => console.error("There was an error getting a verification token", e))
}

<form id="not-the-form" role="form" action="/" onSubmit={onSubmitHandler}>

Answer 1

This should be a SyntheticEvent

Answer 2

I just pulled the semantic-ui-react library and tested. The following works with typescript (assuming you're using the 2nd argument).

import React from "react";
import { Form, FormProps } from "semantic-ui-react";

const Component = () => {
  const handleSubmit = (e: React.FormEvent<HTMLFormElement>, data: FormProps) => {/* your code */};
  return (
      <Form onSubmit={handleSubmit} />
  );
};

If you're not using the data argument then you'd have

  const handleSubmit = (e: React.FormEvent<HTMLFormElement>) => { /* your code */};

The return type that you're thinking typescript is complaining about is automatically determined to be "void" by typescript because the function is not returning any value.

Edit: Your question appears to have changed, and your handler now has 3 arguments. Neither the html <form/> element or the semantic-ui-react <Form/> onSubmit function signatures match what you're passing. It sounds like you're wanting to pass custom arguments to your handler. In which case you'd need to have a higher order function.

const onSubmitHandler = (setVerificationId: type, setVerificationToken: type) = (e: React.FormEvent<HTMLFormElement>) => { /* your code */}

// calling code
<Form onSubmit={onSubmitHandler(setVerificationId, setVerificationToken)}>