Controls share a consistent, signal-backed state model. It lives in two base classes:

• JigBase<T> — the root of every control. Owns presentation/identity state: unstyled, kind, color, and the pt passthrough input.
• ValueControlBase<T> — extends JigBase for form-value controls. Adds the value and interaction state.

The state signals

ValueControlBase exposes these (all boolean inputs use Angular's booleanAttribute transform, so <jig-checkbox disabled> works):

value and touched are two-way model()s; the rest are one-way inputs.

invalid is set by you, not derived

Setting [invalid] is an explicit choice — the control does not flip it automatically from form validation. There is no ControlValueAccessor. Instead:

• Signal forms — controls implement FormValueControl, so they bind directly and a bound field writes invalid in for you.
• Reactive/template forms — a dedicated error directive reads the Angular AbstractControl's errors/touched/dirty and drives a hint control, rather than mutating the control's own invalid.

When the invalid styling actually appears is a separate decision, owned by invalidOn (touched by default, or dirty / immediate / never). The full picture is in Forms & Validation.

State drives theming

State signals are wired to theme classes when a control calls injectThemeTemplate with a mapping. Each entry is a class name mapped to a boolean or a callback that reads a signal:

protected readonly theme = this.injectThemeTemplate(inputControlTemplate, {
  root: true,
  invalid: () => this.invalid(),
  empty: () => !this.value(),
});

When invalid() flips to true, the invalid theme class appears on the host — no manual DOM code. The callbacks are re-evaluated reactively, so they must read signals to stay live. This is the same mechanism Passthrough uses to apply classes.

Inherited state

unstyled cascades from a parent control to its children automatically. disabled is composed where it makes sense — e.g. a radio button is disabled if either it or its group is disabled, and an input-field marks its host inert when disabled so projected controls follow.