Use progressive form enhancement and handle form submissions in Astro. This library only uses native Web APIs and can be used in any runtime.

npm i astro-form-actions
pnpm add astro-form-actions
yarn add astro-form-actions

Documentation: https://github.com/pilcrowOnPaper/astro-form-actions/wiki

Demo: https://astro-form-actions.vercel.app

Need a library to parse your forms? Check out my other project Adria!

• Simple
• Type inference
• Supports multipart form data
• Framework agnostic

This library is made up of 2 parts: server side and client side.

handleFormSubmission will handle all POST requests to the page.

// inside .astro page
import {
	handleFormSubmission,
	reject,
	resolve,
	redirect
} from "astro-form-actions";

const { response, error, inputValues, body } = await handleFormSubmission(
	Astro,
	async (formData) => {
		const message = formData.get("message");
		if (typeof notes !== "string")
			return reject(400, {
				message: "bad input"
			});
		// do some stuff
		return resolve({
			success: true
		});
	}
);
if (response) return response;

You can use a regular HTML form:

<form method="post">
	<input name="message" />
	<input type="submit" />
</form>

Or, by using component frameworks like Solid (or just even vanilla JS), you can use submitForm to make the submission.

import { submitForm } from "astro-form-actions/client";

export default () => {
	return (
		<form
			method="post"
			onSubmit={(e) => {
				e.preventDefault();
				const { error } = await submitForm<
					{
						success: boolean;
					},
					{
						message: string;
					}
				>(e.currentTarget);
			}}
		>
			<input name="message" />
			<input type="submit" />
		</form>
	);
};

Parts of the library is from https://github.com/nachomazzara/parse-multipart-data.