Enumerating Properties of an Object

object.js

const circle = {
  radius: 1,
  draw() {
    console.log('draw');
  }
};

for (let key in circle) {
  console.log(key, circle[key]);
}

for (let key of Object.keys(circle)) {
  console.log(key, circle[key]);
}

for (let entry of Object.entries(circle)) {
  console.log(entry);
}

if ('radius' in circle) {
  console.log('Yes')
}