ES6語法快速入門二

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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