function diff(obj1, obj2) {
const result = {};
if (Object.is(obj1, obj2)) {
return undefined;
}
if (!obj2 || typeof obj2 !== 'object') {
return obj2;
}
Object.keys(obj1 || {}).concat(Object.keys(obj2 || {})).forEach(key => {
if(obj2[key] !== obj1[key] && !Object.is(obj1[key], obj2[key])) {
result[key] = obj2[key];
}
if(typeof obj2[key] === 'object' && typeof obj1[key] === 'object') {
const value = diff(obj1[key], obj2[key]);
if (value !== undefined) {
result[key] = value;
}
}
});
return result;
}