Data Mutations

Back in the good old days, the web main method of applying data mutations was forms. Back-end centered frameworks like Rails and Laravel are still focused around web forms, but the JavaScript ecosystem does not leverage this. Why do we ignore forms? What's easier than a <form />? Most of the hatred comes from a poor user experience and accessibility issues.

Remastered solves data mutations using progressively enhanced forms. When rendered by the server, we use plain old <form /> tags. Then, when JavaScript kicks in, we allow having more complex interactions with the form -- just like the <Link /> tag for URL navigation.

Data mutations is split in two: back-end and front-end.


The back-end part of the data mutations is a special function exported from a route, which is called action. This function gets a Request and returns a Response. It will be triggered when the route will receive a request that isn't GET, so e.g. POST, PUT, DELETE:

// app/routes/my-route.tsx

import { redirectTo, ActionFn } from "remastered";

export const action: ActionFn = async ({ request }) => {
  console.log("Do something with the request?");
  request.method; // POST, PUT, DELETE...

  const data = new URLSearchParams(await request.text());

  return redirectTo("/");

// of app...

In your action you can use sessions to authenticate users and add error flashes.

Note: it's very likely that most of your actions will return a redirect response, like redirecting to a new item that was created in database, or back to the form page, etc.


When using action functions, you can use a plain old form. This will work without any JavaScript enabled. 😉

If you want to have a more complex interaction, like the following -- you can use the useForm hook to get a dynamic behavior:

  • Focus handling
  • Multiple parallel submits
  • Optimistic UI

The useForm is a React hook that returns multiple values back:

  • a Form component
  • pendingSubmits
import { useForm } from "remastered";

function MyComponent() {
  const [Form, pendingSubmits] = useForm();

  return (
    <Form method="post" action="/">
      <input type="text" name="message" />
      <button type="submit">Submit</button>

The Form component, which is a small bounded wrapper around form that hooks into onSubmit that submits the value. This is a drop-in replacement for the <form /> component -- replace the form with a capitalized Form and that's it -- you have a JavaScript-enabled form.

Working with it is almost the same as you would use a form tag. They work the same way to allow the back-end to be agnostic.

When the form submits, it will add an entry to the pendingSubmits array -- which tracks the "in-flight" requests, and can be used for optimistic UI and focus management.

Each PendingSubmit is an object with:

  • method: the form method
  • action: the form action
  • encType: the form encoding type (the Content-Type being sent to the server). note: the default content type is application/x-www-urlencoded. If you want to upload files, set the encType of the Form to form-data/multipart
  • data: a FormData instance contains the data that is being sent to the server. note: highly valuable for optimistic ui!

Optimistic UI

You can use the data key to provide optimistic UI:

import { getTweets, Tweet } from "~app/model/Tweet";
import { useForm, useRouteData, LoaderFn } from "remastered";

export const loader: LoaderFn<Tweet[]> = async () => {
  return getTweets();

export default function AllTweets() {
  const storedTweets = useRouteData();
  const [Form, pendingSubmits] = useForm();

  const pendingTweets = Tweet => {
    return {

  const allTweets = [...pendingTweets, ...storedTweets];

  return (
        { => ...)}

This page was generated with Remastered v0.1.34 at

Wanna talk? Feel free to tweet at @galstar.