simpleClone () {
		const toFlat = ["date", "sunrise", "sunset"];
		let clone = { ...this };
		for (const prop of toFlat) {
			clone[prop] = clone?.[prop]?.valueOf() ?? clone?.[prop];
		}
		return clone;
	}
Clone to simple object to prevent mutating and deprecation of legacy library.

Before being handed to other modules, mutable values must be cloned safely.
Especially 'moment' object is not immutable, so original 'date', 'sunrise', 'sunset' could be corrupted or changed by other modules.
@returns {object} plained object clone of original weatherObject