js for each for of for in的代码示例

好的，以下是三种循环的代码示例：

1. for 循环

const arr = [1, 2, 3, 4, 5];
for (let i = 0; i < arr.length; i++) {
 console.log(arr[i]);
}

2. forEach 循环

const arr = [1, 2, 3, 4, 5];
arr.forEach((item) => {
  console.log(item);
});

3. for...of 循环

const arr = [1, 2, 3, 4, 5];
for (const item of arr) {
  console.log(item);
}

4. for...in 循环

const obj = { a: 1, b: 2, c: 3 };
for (const key in obj) {
  console.log(`${key}: ${obj[key]}`);
}