js的几种循环

// 数组
let a = ["aa", "11", "cc", "gg"];
// 对象
let b = {a: "aa", b: 11, c: "q12"};

console.log('--------------------------常规for 数组');
for (let i = 0; i < a.length; i++) {
  console.log(i, a[i]);
}
console.log('--------------------------while 数组');
let m = 0;
while (m < a.length) {
  console.log(m, a[m]);
  m++;
}
console.log('--------------------------do while 数组');
let n = 0;
do {
  console.log(n, a[n]);
  n++;
} while (n < a.length)
console.log('--------------------------for in 数组');
for (let index in a) {
  console.log(index, a[index]);
}
console.log('--------------------------for in 对象');
for (let key in b) {
  console.log(key, b[key]);
}
console.log('--------------------------for of 数组');
for (let value of a) {
  console.log(value);
}
console.log('--------------------------forEach 数组 (回调)');
a.forEach((value, index, array) => {
  console.log(value, index, array);
})

--------------------------常规for 数组
0 aa
1 11
2 cc
3 gg
--------------------------while 数组
0 aa
1 11
2 cc
3 gg
--------------------------do while 数组
0 aa
1 11
2 cc
3 gg
--------------------------for in 数组
0 aa
1 11
2 cc
3 gg
--------------------------for in 对象
a aa
b 11
c q12
--------------------------for of 数组
aa
11
cc
gg
--------------------------forEach 数组 (回调)
aa 0 [ 'aa', '11', 'cc', 'gg' ]
11 1 [ 'aa', '11', 'cc', 'gg' ]
cc 2 [ 'aa', '11', 'cc', 'gg' ]
gg 3 [ 'aa', '11', 'cc', 'gg' ]