const a = Symbol()
const obj1 = {
[a]: 1
}
const obj2 = {b: 2}
const obj3 = {}
Object.defineProperty(obj3, 'a', {
value: 1,
enumerable: false
})
const obj4 = {}
console.log(Reflect.ownKeys(obj1).length === 0) // false
console.log(Reflect.ownKeys(obj2).length === 0) // false
console.log(Reflect.ownKeys(obj3).length === 0) // false
console.log(Reflect.ownKeys(obj4).length === 0) // true