JavaScript中 ES6變量的結(jié)構(gòu)賦值

let x = 1;
let y = 2;
[x,y] = [y,x]

//返回一個數(shù)組
function example(){
 return [1,2,3];
}
let [a,b,c] = example();
[a,b,c]; //[1,2,3]
//返回一個對象
function example(){
 return {
 foo:1,
 bar:2
 };
}
let {foo,bar} = example();
foo; //1
bar; //2

//參數(shù)是一組有次序的值
function f([x,y,z]){
 console.log(x,y,z);
}
f([1,2,3]); //1,2,3
//參數(shù)是一組無次序的值
function func({x,y,z}){
 console.log(x,y,z);
}
func({z:3,y:2,x:1}); //1,2,3

let jsonData = {
 id:42,
 status:"OK",
 data:[123,456] 
} ;
let {id,status,data:number} = jsonData;
console.log(id,status,number); //42 "OK" (2) [123, 456]

var map = new Map();
map.set('first','hello');
map.set('second','world');

for(let [key,value] of map){
 console.log(key,value);
}

//first hello
//second world

//獲取鍵名
for(let [key] of map){
 console.log(key);
}

//first
//second
//獲取鍵值
for(let [,value] of map){
 console.log(value);
}
//hello
//world

const {a,b} = require('source-map');