Mounted Form

mountForm returns a MountedForm. Keep it when the host app needs cleanup, direct engine access, or design system updates.

Property or method	Type	Purpose
form	FormController	Read values, validate, submit, reset, or subscribe.
host	HTMLElement	Mounted primitive host element.
engineRegistry	Registry	Field and report definitions used by this instance.
primitiveRegistry	PrimitiveRegistry	Renderer mapping used by this instance.
designSystemRegistry	DesignSystemRegistry	Theme and recipe registry.
designSystem	AttachedDesignSystem	Attached stylesheet/controller.
updateDesignSystem(config)	void	Merge design system changes.
replaceDesignSystem(snapshot)	void	Replace mode, theme, recipe, and overrides.
resetDesignSystem()	void	Restore kit defaults.
unmount()	void	Abort submit, disconnect styles, and remove the host.

const mounted = mountForm(container, {
  transport: createJsonTransport({ endpoint: "/api/predict" }),
  schema,
});

mounted.form.subscribe((state) => {
  console.log(state.status, state.valid);
});

window.addEventListener("beforeunload", () => mounted.unmount());

Calling mountForm again on the same container unmounts the previous MLForm instance before mounting the next one.