Bonus tip: how to turn your POO (plain old object) into an iteratable array!
const obj1 = {a: 1, b: 2};
obj1.__proto__[Symbol.iterator] = function* () {
for (const k in this) yield [k, this[k]];
}
for (const e of obj1) console.log(e.join(":"))
// a:1
// b:2