const sym1 = Symbol('id');
const sym2 = Symbol('id');

const obj = {
  [sym1]: 'first',
  [sym2]: 'second',
  regular: 'value'
};

const s = Symbol.for('shared');
const s2 = Symbol.for('shared');

console.log(
  sym1 === sym2,
  Object.keys(obj).length,
  Reflect.ownKeys(obj).length,
  s === s2,
  sym1.toString()
);