symbol13.js

let foo = {
  [Symbol()]: 'foo',
  [Symbol('foo')]: 'bar',
  [Symbol.for('bar')]: 'baz',
  propriedade: 'legal'
}

console.log(Object.getOwnPropertySymbols(foo)) // [ Symbol(), Symbol(foo), Symbol(bar) ]

for (let symbol of Object.getOwnPropertySymbols(foo)) {
  console.log(foo[symbol])
  // 'foo'
  // 'bar'
  // 'baz'
}