for of 不能遍歷對(duì)象赌朋，for in 可以
對(duì)比兩段對(duì)象的遍歷代碼
for in
let b = {m: 1,n: 2,p: 3,q: 4}
for (let i in b) {
if (i == "p") {
break
}
console.log(i,b[i]);
}
運(yùn)行結(jié)果為：
m 1
n 2
for of
let b = {m: 1,n: 2,p: 3,q: 4}
for (let i of b) {
if (i == "3") {
break
}
console.log(i,b[i]);
}
運(yùn)行則會(huì)報(bào)錯(cuò)
兩者都可以遍歷數(shù)組，for in 可以遍歷出鍵和值篇裁，for of 只能遍歷出值
對(duì)比兩段數(shù)組的遍歷代碼
for in
let a = ['c', 'd', 'e', 'f']
for (let i in a) {
if (i == 2) {
break
}
console.log(i,a[i]);
}
運(yùn)行結(jié)果為：
0 c
1 d
for of
let a = ['c', 'd', 'e', 'f']
for (let i of a) {
if (i == "e") {
break
}
console.log(i);
}
運(yùn)行結(jié)果為
c
d
