SOURCE

var myIterable = {
    *[Symbol.iterator] (){
        yield 1;
        yield 2;
        yield 3;
    }
}
console.log([...myIterable]);
for(let i of myIterable){
    console.log(i);
}

var obj = {
  a: 1,
  b: 2,
};

for(let i of obj){
    console.log(i);
}