JS ****************

let [x, [y, z]] = ['hello', ['JavaScript', 'ES6']];
x; // 'hello'
y; // 'JavaScript'
z; // 'ES6'



let [, , z] = ['hello', 'JavaScript', 'ES6']; // 忽略前两个元素，只对z赋值第三个元素
z; // 'ES6'


var person = {
    name: '小明',
    age: 20,
    gender: 'male',
    passport: 'G-12345678',
    school: 'No.4 middle school',
    address: {
        city: 'Beijing',
        street: 'No.1 Road',
        zipcode: '100001'
    }
};
var {name, address: {city, zip}} = person;
name; // '小明'
city; // 'Beijing'
zip; // undefined, 因为属性名是zipcode而不是zip
// 注意: address不是变量，而是为了让city和zip获得嵌套的address对象的属性:
address; // Uncaught ReferenceError: address is not defined


var person = {
    name: '小明',
    age: 20,
    gender: 'male',
    passport: 'G-12345678',
    school: 'No.4 middle school'
};


// 把passport属性赋值给变量id:
let {name, passport:id} = person;
name; // '小明'
id; // 'G-12345678'
// 注意: passport不是变量，而是为了让变量id获得passport属性:
passport; // Uncaught ReferenceError: passport is not defined


var person = {
    name: '小明',
    age: 20,
    gender: 'male',
    passport: 'G-12345678'
};


// 如果person对象没有single属性，默认赋值为true:
var {name, single=true} = person;
name; // '小明'
single; // true


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

apply、call

function getAge() {
    var y = new Date().getFullYear();
    return y - this.birth;
}

var xiaoming = {
    name: '小明',
    birth: 1995,
    age: getAge
};

xiaoming.age(); // 25
getAge.apply(xiaoming, []); // 25, this指向xiaoming, 参数为空
getAge.call(xiaoming);

.