Object.entries()

const object1 = {
  a: "somestring",
  b: 42,
};

for (const [key, value] of Object.entries(object1)) {
  console.log(`${key}: ${value}`);
}

// 範例輸出：
// "a: somestring"
// "b: 42"

Object.entries(obj)

const obj = { foo: "bar", baz: 42 };
console.log(Object.entries(obj)); // [ ['foo', 'bar'], ['baz', 42] ]

const arrayLike = { 0: "a", 1: "b", 2: "c" };
console.log(Object.entries(arrayLike)); // [ ['0', 'a'], ['1', 'b'], ['2', 'c'] ]

const randomKeyOrder = { 100: "a", 2: "b", 7: "c" };
console.log(Object.entries(randomKeyOrder)); // [ ['2', 'b'], ['7', 'c'], ['100', 'a'] ]

// getFoo 是不可枚舉的屬性
const myObj = Object.create(
  {},
  {
    getFoo: {
      value() {
        return this.foo;
      },
    },
  },
);
myObj.foo = "bar";
console.log(Object.entries(myObj)); // [ ['foo', 'bar'] ]

// 字串具有作為可枚舉自身屬性的索引
console.log(Object.entries("foo")); // [ ['0', 'f'], ['1', 'o'], ['2', 'o'] ]

// 除 undefined 和 null 之外的其它原始型別沒有自己的屬性
console.log(Object.entries(100)); // []

const obj = { foo: "bar", baz: 42 };
const map = new Map(Object.entries(obj));
console.log(map); // Map(2) {"foo" => "bar", "baz" => 42}

// 使用 for...of 迴圈
const obj = { a: 5, b: 7, c: 9 };
for (const [key, value] of Object.entries(obj)) {
  console.log(`${key} ${value}`); // "a 5", "b 7", "c 9"
}

// 使用陣列方法
Object.entries(obj).forEach(([key, value]) => {
  console.log(`${key} ${value}`); // "a 5", "b 7", "c 9"
});