Function optionalDef

src/lib/item-input/misc.ts:195–226

(inputDef: InputDefinition<T>, checkIsActive: OptionalDefPredicateFn, options?: OptionalDefOptions)

 *     it would be useful.
 */
export const optionalDef = <T>(inputDef: InputDefinition<T>, checkIsActive: OptionalDefPredicateFn, options?: OptionalDefOptions): InputDefinition<T | undefined> => {
	// In certain situations we need to know if the def has changed.
	let isActive = options?.initiallyActive ?? false
	const decideAndSave = (context?: unknown[]): boolean => {
		isActive = checkIsActive(context)
		return isActive
	}
	const buildFromUserInput = async (context?: unknown[]): Promise<T | undefined | CancelAction> =>
		decideAndSave(context) ? inputDef.buildFromUserInput(context) : undefined
	const summarizeForEdit = (value: T | undefined, context?: unknown[]): string | Uneditable =>
		isActive ? inputDef.summarizeForEdit(value as T, context) : uneditable
	const updateFromUserInput = async (original: T | undefined, context?: unknown[]): Promise<T | undefined | CancelAction> =>
		isActive
			? (original ? inputDef.updateFromUserInput(original as T, context) : inputDef.buildFromUserInput(context))
			: undefined

	const updateIfNeeded = async (original: T | undefined, updatedPropertyName: string | number | symbol, context?: unknown[]): Promise<T | undefined | CancelAction> => {
		const previouslyActive = isActive
		const currentlyActive = decideAndSave(context)
		if (previouslyActive && currentlyActive) {
			return inputDef.updateIfNeeded
				? inputDef.updateIfNeeded(original as T, updatedPropertyName, context)
				: original
		}
		if (currentlyActive && !previouslyActive) {
			return inputDef.buildFromUserInput(context)
		}
		return undefined
	}

	return { name: inputDef.name, buildFromUserInput, summarizeForEdit, updateFromUserInput, updateIfNeeded }
}