ES6为我们提供了for-in循环和for-Each循环还要强大
之前的for-in循环
var arr=['apple','orange','banana','strawberry'];
for (var i in arr) {
console.log(i);
}
//打印的是索引值
0,1,2,3
for-of循环
遍历数组
var arr=['apple','orange','banana','strawberry'];
for (var i in arr) {
console.log(i);
}
//打印的是每一项的值
apple
orange
banana
strawberry
也可以遍历字符串
var string = "boa";
for (var value of string) {
console.log(value);
}
// "b"
// "o"
// "o"
遍历Map对象
let iterable = new Map([["a", 1], ["b", 2], ["c", 3]]);
for (let entry of iterable) {
console.log(entry);
}
// [a, 1]
// [b, 2]
// [c, 3]
for (let [key, value] of iterable) {
console.log(value);
}
// 1
// 2
// 3
