@domphy/form

Headless form state, validation, and submission for Domphy apps: typed values, per-field and form-level (sync + async) validators, touched/blurred/dirty tracking, arrays, and Standard Schema support.

This package is a 1-1 port of @tanstack/form-core v1.33.0 (MIT, © Tanner Linsley and the TanStack team). The src/ is kept byte-identical to upstream, so the entire TanStack Form reference applies as-is and future versions can be diffed and merged directly. The only addition is the Domphy adapter in src/domphy/.

It supersedes the ad-hoc FormState / FieldState that used to live in @domphy/ui.

Install

npm install @domphy/form @domphy/core

@domphy/core is a peer dependency of the adapter only.

Quick Example

import { createForm } from "@domphy/form/domphy"
import type { DomphyElement } from "@domphy/core"
import { button, inputText } from "@domphy/ui"

const form = createForm<{ email: string; password: string }>({
  defaultValues: { email: "", password: "" },
  onSubmit: async ({ value }) => {
    await api.login(value)
  },
})

const email = form.field<string>("email", {
  validators: { onChange: ({ value }) => (value.includes("@") ? undefined : "Invalid email") },
})

const App: DomphyElement<"form"> = {
  form: [
    {
      input: null,
      $: [inputText()],
      value: (l) => email.value(l),
      onInput: (e) => email.handleChange((e.target as HTMLInputElement).value),
      onBlur: () => email.handleBlur(),
    },
    {
      div: (l) => String(email.errors(l)[0] ?? ""),
      hidden: (l) => email.errors(l).length === 0,
    },
    {
      button: (l) => (form.isSubmitting(l) ? "Signing in…" : "Sign in"),
      $: [button({ color: "primary" })],
      type: "submit",
      ariaDisabled: (l) => !form.canSubmit(l),
    },
  ],
  onSubmit: (e) => {
    e.preventDefault()
    form.handleSubmit()
  },
  _onRemove: () => form.destroy(),
}

Adapter API

createForm(options) returns a handle:

| Member | Description | | --- | --- | | values(l) / state(l) | Reactive form values / full form state. | | canSubmit(l) / isSubmitting(l) / isValid(l) / isSubmitted(l) | Reactive form flags. | | field<TData>(name, options?) | Creates and mounts a reactive field handle. | | handleSubmit() | Runs validation and submission. | | reset(values?) | Resets to defaults (or given values). | | form | The underlying FormApi — the full form-core API. | | version(l) | Raw reactive change counter. | | destroy() | Unmounts the form and all fields; call from _onRemove. |

A field handle from field(name, options):

| Member | Description | | --- | --- | | value(l) | Reactive field value — bind to the input's value. | | errors(l) / meta(l) | Reactive validation errors / full field meta. | | handleChange(value) | Update the value (call from onInput). | | handleBlur() | Mark blurred and run blur validators. | | setValue(updater) | Set the value programmatically. | | api | The underlying FieldApi. |

Field and form options (validators, async debouncing, listeners, array helpers, Standard Schema, …) are the upstream form-core options — see the TanStack Form docs.