一、解構賦值
1.對象的解構賦值
let obj = {
a:1,
b:3
};
// console.log(obj)
// let a=obj.a;
// let b=obj.b;
// console.log(a,b)
let {a,b}=obj;
console.log(a,b);
2.數組的解構賦值
let arr=["a","b","c"];
let [e,f]=arr;
console.log(e,f);
問題:let a=0; let b=1;//怎樣快速交換a,b的值?
[a,b]=[b,a];
3.字符串解構賦值
let str="abc";
let [e,f]=str;
console.log(e,f);
二、展開運算符
1.數組展開:
let arr=[1,2,3,4];
let arr2=["a","b",...arr,"c","d"];
console.log(arr2);
打印結果如下圖:
剩餘參數
let arr=[1,2,3,4];
let[a,b,...c]=arr;
console.log(a,b,c);//1,2,[3,4]
2.對象展開:
let obj = {
a:1,
b:2
};
let obj2 = {
...obj,
c:3,
d:4
};
console.log(obj2);//{a:1,b:2,c:3,d:4}
let {a,b,...c} = obj2;
console.log(a,b,c);//1,2,{c:3,d:4}
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