ES6解构赋值实例详解

let [x, y, ...z] = ['a']
//"a", undefined, []

let [x, y, z] = new Set(["a", "b", "c"])
x //"a"

[x=1, y=2, z=3, o=4] = ['a', , undefined, null]
//"a", 2, 3, null

var {bar, foo, baz: loc} = {foo: 'aaa', baz: 'bbb'}
bar //undefined
foo //"aaa"
loc //"bbb"
baz //ReferenceError: baz is not defined

var node = {
  loc: {
    start: {
      line: 1,
      column: 5
    }
  }
}
var {loc:{start:{line}}} = node
line //1
loc //ReferenceError: loc is not defined
start //ReferenceError: start is not defined

var x;
{x}={x:1} //SyntaxError: Unexpected token =
({x}={x:1}) //正确

const [a,b] = 'hello' a//h
let {length:len} = 'hello' len//5(字符串本身包含length属性)

let a = true
{b} = {a}
//Object {a: true}

[[1,2],[3,4]].map((a,b)=>a+b) //[3,7]
function({x=0,y=0}={}){
  return [x,y]
}

({
  needServicePwd: this.needServicePwd,
  needImgCode: this.needImgCode,
  needSmsCode: this.needSmsCode
} = data)

var map = new Map();
map.set('first', 'hello');
map.set('second', 'world');
for (let [key, value] of map) {
  console.log(key + " is " + value);
}

const { SourceMapConsumer, SourceNode } = require("source-map");