Felte: A form library for Svelte, Solid and React

Felte is a simple to use form library for Svelte, Solid and React. No Field or Form components are needed, just plain stores and actions to build your form however you like. You can see it in action in this CodeSandbox demo!

Features

Single action to make your form reactive.
Use HTML5 native elements to create your form. (Only the name attribute is necessary).
Provides stores and helper functions to handle more complex use cases.
No assumptions on your validation strategy. Use any validation library you want or write your own strategy.
Handles addition and removal of form controls during runtime.
Official solutions for error reporting using reporter packages.
Well tested. Currently at 99% code coverage and constantly working on improving test quality.
Supports validation with yup, zod, superstruct and vest.
Easily extend its functionality.

Simple usage example

Svelte

<script>
  import { createForm } from 'felte';

  const { form } = createForm({
    onSubmit: async (values) => {
      /* call to an api */
    },
  });
</script>

<form use:form>
  <input type="text" name="email" />
  <input type="password" name="password" />
  <button type="submit">Sign In</button>
</form>

Solid

import { createForm } from '@felte/solid';

function Form() {
  const { form } = createForm({
    onSubmit: async (values) => {
      /* call to an api */
    },
  });

  return (
    <form use:form={form}>
      <input type="text" name="email" />
      <input type="password" name="password" />
      <button type="submit">Sign In</button>
    </form>
  );
}

Important

To use the use-* directive on Solid. You need to extend the JSX namespace. For example:

// src/global.d.ts
declare global {
  declare module "solid-js" {
    namespace JSX {
      interface Directives {
        form: (node: HTMLFormElement) => void;
      }
    }
  }
}

React/Preact

import { useForm } from '@felte/react';
// if using preact, use `@felte/preact`

function Form() {
  const { form } = useForm({
    onSubmit: async (values) => {
      /* call to an api */
    },
  });

  return (
    <form ref={form}>
      <input type="text" name="email" />
      <input type="password" name="password" />
      <button type="submit">Sign In</button>
    </form>
  );
}

Vue

<script setup>
  import { useForm } from '@felte/vue';

  const { vForm } = useForm({
    onSubmit: async (values) => {
      /* call to an api */
    },
  });
</script>
<template>
  <form v-form>
    <input type="text" name="email" />
    <input type="password" name="password" />
    <button type="submit">Sign In</button>
  </form>
</template>

VanillaJS with Web Components

<script type="module">
  import 'https://unpkg.com/@felte/element@0.4.0/dist/min/felte-form.js';
  const felteForm = document.querySelector('felte-form');

  felteForm.configuration = {
    onSubmit: async (values) => {
      console.log(values);
    },
  };
</script>

<felte-form>
  <form>
    <input type="text" name="email" />
    <input type="password" name="password" />
    <button type="submit">Sign In</button>
  </form>
</felte-form>

This example works without a bundler! Copy its contents to an HTML file and open it on your browser. A more complete example like this, with validation and error reporting, can be found here.

More examples

You can find fully functional examples on the /examples directory of this repository. You should be able to open them on CodeSandbox by replacing github's url to githubbox. E.g. Replace https://github.com/pablo-abc/felte/tree/main/examples/svelte/basic with https://githubbox.com/pablo-abc/felte/tree/main/examples/svelte/basic.

Packages

This repository is a mono-repo containing multiple packages located in the packages directory. Maintained using pnpm and Changesets.

Svelte

We provide two packages that are specific to Svelte:

felte

This is the core package that contains all the basic functionality you need to handle your forms in Svelte. Felte optionally allows you to use error reporters (see them as plugins) to prevent you from needing to find a way to display your errors on your form manually. For this we provide already some reporter packages contained in this same repo.

@felte/reporter-svelte

A reporter package that uses a Svelte component to pass the validation messages for you to display. This provides an API that might feel the most familiar to most developers.

Solid

We provide two packages that are specific to Solid:

@felte/solid

This is the core package that contains all the basic functionality you need to handle your forms in Solid. Same as felte but specifically made for Solid.

@felte/reporter-solid

A reporter package that uses a Solid component to pass the validation messages for you to display. This provides an API that might feel the most familiar to most developers.

React

We provide two packages that are specific to React:

@felte/react

This is the main package that contains the basic functionality you need to handle your forms in React. Same as felte but specifically made for React.

@felte/reporter-react

A reporter packages that uses a React component to pass the validation messages for you to display. This provides an API that might feel the most familiar to most developers.

Preact

We provide two packages that are specific to Preact:

@felte/preact

This is the main package that contains the basic functionality you need to handle your forms in Preact. Same as felte but specifically made for Preact. The API is the same as @felte/react so you can refer to the same documentation.

@felte/reporter-preact

A reporter packages that uses a Preact component to pass the validation messages for you to display. This provides an API that might feel the most familiar to most developers. The API is the same as @felte/react so you can refer to the same documentation.

Vue

We provide (experimental) support for Vue with the following package:

@felte/vue

This is package contains the basic functionality you need to handle your forms in Vue. Same as felte but specifically made for Vue. The API is similar to that of felte but using a custom directive to register your form and returning "accessors" (similar to the react/preact/solid packages) that resolve into reactive refs.

There's no documentation for this right now so use at your own risk.

VanillaJS

We provide three packages that can be used with only VanillaJS. Two of them using Web Components. These elements do not use the shadow DOM since there is no reason to isolate styles.

@felte/element

This is the main package that contains the basic functionality you need to handle your forms in vanilla JS using a custom element. Similar to felte but specifically made to be used as a custom element. This is the recommended way to handle your forms when using Vanilla JS. Web components are well supported by all major browsers so this should be a safe option unless you need to support legacy browsers.

@felte/reporter-element

A reporter packages that uses a custom element to display validation messages on the DOM. This the recommended way to display your validation messages when using vanilla JS.

@felte/vanilla

This is the main package that contains the basic functionality you need to handle your forms in vanilla JS. Similar to felte and other integrations but with all code related to frameworks removed. This requires a bit more work to use, since you'll be the one in charge of cleaning up subscribers and listeners on it. It's API is basically the same as felte (Svelte's integration) so you can use Svelte's documentation as a reference. This can be used as a starting point to create your own integration/package for other environments. When it comes to vanilla JS we'd recommend using @felte/element using web components.

Validators

The following packages can be used with any of the framework specific felte wrappers:

@felte/validator-yup

A utility package to help you validate your form with Yup.

@felte/validator-zod

A utility package to help you validate your form with Zod.

@felte/validator-superstruct

A utility package to help you validate your form with Superstruct.

@felte/validator-vest

A utility package to help you validate your form with Vest.

Reporters

The following packages can be used with any of the framework specific felte wrappers:

@felte/reporter-tippy

A reporter that uses Tippy.js to display your validation messages without needing any extra work.

@felte/reporter-cvapi

A reporter that uses the browser's constraint validation API to display your validation messages.

@felte/reporter-dom

A reporter that displays the error messages in the DOM, either as a single element or a list of elements.

Contributing

If you want to contribute to this project you may check CONTRIBUTING.md for general guidelines on how to do so.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

_{Pablo Berganza} 💻 📖 🤔 🚧 ⚠️	_{Panagiotis Kapros} 💻	_{Benjamin Bender} 💻 🤔 📖	_{Abhijit Kar ツ} 🐛 🤔	_{Hugo Maestá} 💻 🤔	_{websocket98765} 🐛	_avimar 📖
_{Umang Galaiya} 💻 🐛	_{Gildas Garcia} 💻 🐛	_basaran 💻 🐛	_Evyatar 💻	_{Julian Schurhammer} 💻	_{Koichi Kiyokawa} 📖	_{Ryan Christian} 📖
_{Ikko Ashimine} 📖	_pasqui23 💻	_{Immanuel Calvin Herchenbach} 📖	_dawidmachon 📖	_{Emil Celustka} 💻	_{Callum Macdonald} 📖	_Jason 📖
_{John Winston} 💻	_{Timo Wilhelm} 💻	_jfreyheit 📖	_{Urs Honegger} 📖	_{Bradley Lewis} 📖	_{Julien Tome} 💻	_xvenge00 💻
_{Alfredo Maria Milano} 💻	_{Carlo Taleon} 📖	_{John Paul Calvo} 💻

This project follows the all-contributors specification. Contributions of any kind welcome!

License

MIT

Browser support

While further testing would be needed to provide an accurate answer, Felte should work in all evergreen browsers. Polyfills might be needed if you target older browsers such as IE 11 for, at least, Promise.all, Element.closest, URLSearchParams, fetch, CustomEvent and iterators.