enums

const obj = {
  [Symbol("my_key")]: 1,
  [Symbol("second_key")]: 2,
  enum: 3,
  nonEnum: 4,
};

Object.defineProperty(obj, "nonEnum", {
  enumerable: false,
});

// Ignores symbol-valued property keys:
console.log(Object.getOwnPropertyNames(obj));
// ['enum', 'nonEnum']

// Ignores string-valued property keys:
console.log(Object.getOwnPropertySymbols(obj));
// [ Symbol("my_key"), Symbol("second_key") ]

// Considers all kinds of keys:
console.log(Reflect.ownKeys(obj));
// [ "enum", "nonEnum", Symbol("my_key"), Symbol("second_key") ]

// Only considers enumerable property keys that are strings:
console.log(Object.keys(obj));
// ['enum']