propsDependsOn

propsDependsOn is an array of rules. Each rule names its source fieldNames and a compute function returning a Partial<RuntimeProps> that is merged into the target.

Props you can return

hidden, required, readOnly, disabled, options, min, max, minDate, maxDate, placeholder, prefix, suffix, description, label, className. (Groups meaningfully use hidden, title, description, className.)

Example: dependent options + show/hide

Selecting a country fills the region options; checking "gift" reveals and requires the message field.

{
	key: 'region',
	label: 'Region',
	control: 'dropdown',
	options: [],
	dependents: {
		propsDependsOn: [{
			fieldNames: ['country'],
			compute: (v) => ({
				options: REGIONS[v.country] ?? [],
				disabled: !v.country,
				placeholder: v.country ? 'Pick a region' : 'Pick a country first',
			}),
		}],
	},
}

Multiple rules

Provide several rules with disjoint source sets; the engine subscribes to each independently. When two rules write the same prop, the later rule wins (last-write).

dependents: {
	propsDependsOn: [
		{ fieldNames: ['plan'], compute: (v) => ({ hidden: v.plan === 'free' }) },
		{ fieldNames: ['region'], compute: (v) => ({ required: v.region === 'eu' }) },
	],
}

clearWhenHidden

By default a field's value is cleared when it becomes hidden (default true). Set clearWhenHidden: false to preserve the value across show/hide.