process = (options, normalizeSimple, normalizeOptions, fn) => {
	/**
	 * @param {(string | Item<T>)[]} items items
	 */
	const array = items => {
		for (const item of items) {
			if (typeof item === "string") {
				fn(item, normalizeSimple(item, item));
			} else if (item && typeof item === "object") {
				object(item);
			} else {
				throw new Error("Unexpected options format");
			}
		}
	};
	/**
	 * @param {Item<T>} obj an object
	 */
	const object = obj => {
		for (const [key, value] of Object.entries(obj)) {
			if (typeof value === "string" || Array.isArray(value)) {
				fn(key, normalizeSimple(value, key));
			} else {
				fn(key, normalizeOptions(value, key));
			}
		}
	};
	if (!options) {
		// Do nothing
	} else if (Array.isArray(options)) {
		array(options);
	} else if (typeof options === "object") {
		object(options);
	} else {
		throw new Error("Unexpected options format");
	}
}
@template T
@template N
@param {ContainerOptionsFormat<T>} options options passed by the user
@param {(item: string | string[], itemOrKey: string) => N} normalizeSimple normalize a simple item
@param {(value: T, key: string) => N} normalizeOptions normalize a complex item
@param {(item: string, normalized: N) => void} fn processing function
@returns {void}