const isValidObject = obj => typeof obj === 'object' && obj;
const xorFlags = (first, second) => !(first && second) && (first || second);
const arrayHasDifferece = (origin, override) => JSON.stringify(origin) === JSON.stringify(override);
const differentTypes = (origin, override) => typeof origin !== typeof override
	|| xorFlags(Array.isArray(origin), Array.isArray(override));
const objectDiff = (origin, override) => {
	if (!isValidObject(origin) || !isValidObject(override)) {
		return override;
	}
	const diff = {};
	const overrideKeys = Object.keys(override);
	overrideKeys.forEach((key) => {
		if (origin[key] === override[key]) {
			return;
		}
		if (differentTypes(origin[key], override[key])) {
			diff[key] = override[key];
			return;
		}
		if (Array.isArray(origin[key]) && Array.isArray(override[key])) {
			if (arrayHasDifferece(origin[key], override[key])) {
				diff[key] = override[key];
			}
			return;
		}
		if (typeof origin[key] === 'object' && typeof override[key] === 'object') {
			const diffProperty = objectDiff(origin[key], override[key]);
			if (diffProperty) {
				diff[key] = diffProperty;
			}
			return;
		}
		if (origin[key] !== override[key]) {
			diff[key] = override[key];
		}
	});
	const diffKeys = Object.keys(diff);
	if (diffKeys.length) {
		return diff;
	}
};
module.exports = objectDiff;