const a = {
  name: "Hobby",
  gender: "female",
};

const b = {...a};

a.gender = "male";

console.log("a:", a);
console.log("b:", b);
console.log("a === b", a === b);

/* console 結果
a: {
  name: "Hobby",
  gender: "male"
}

b: {
  name: "Hobby",
  gender: "female"
}

a === b false
*/