// 創(chuàng)建數(shù)組
let arr = [1,2,3]; 
// 獲取數(shù)組元素
console.log(arr[0]); // 輸出 1
// 修改數(shù)組元素
array[0] = 5;		 // 數(shù)組元素變成了 [5,2,3]
// 遍歷數(shù)組元素，其中 length 是數(shù)組屬性，代表數(shù)組長度
for(let i = 0; i < arr.length; i++) {
    console.log(arr[i]);
}

let arr = [1,2,3]; 
arr.push(4);    	// 向數(shù)組尾部(右側(cè))添加元素, 結(jié)果 [1,2,3,4]
arr.shift();		// 從數(shù)組頭部(左側(cè))移除元素, 結(jié)果 [2,3,4]
arr.splice(1,1);	// 刪除【參數(shù)1】索引位置的【參數(shù)2】個元素，結(jié)果 [2,4]

let arr = ['a','b','c'];
arr.join(); 		// 默認(rèn)使用【,】作為連接符，結(jié)果 'a,b,c'
arr.join('');		// 結(jié)果 'abc'
arr.join('-');		// 結(jié)果 'a-b-c'

let arr = [1,2,3,6];
function a(i) {   // 代表的新舊元素之間的變換規(guī)則
    return i * 10
}
// arr.map(a) // 具名函數(shù)，結(jié)果 [10,20,30,60]
// arr.map( (i) => {return i * 10} ); // 箭頭函數(shù)
arr.map( i => i * 10 ); // 箭頭函數(shù)

function map(a) { // 參數(shù)是一個函數(shù)
    let narr = [];
    for(let i = 0; i < arr.length; i++) {
        let o = arr[i]; // 舊元素
        let n = a(o);   // 新元素
        narr.push(n);
    }
    return narr;
} 

let arr = [1,2,3,6];
arr.filter( (i)=> i % 2 == 1 ); // 結(jié)果 [1,3]

let arr = [1,2,3,6];
/*for(let i = 0; i < arr.length; i++) {
    console.log(arr[i]);
}*/
arr.forEach( (i) => console.log(i) );

let obj = {
    屬性名: 值,
    方法名: 函數(shù),
    get 屬性名() {},
    set 屬性名(新值) {}
}

let stu1 = {
    name: "小明",
    age: 18,
    study: function(){
        console.log(this.name + "愛學(xué)習(xí)");
    }    
}

let name = "小黑";
let age = 20;
let study = function(){
    console.log(this.name + "愛學(xué)習(xí)");
}
let stu2 = { name, age, study }

let stu3 = {
    name: "小白",
    age: 18,
    study(){
        console.log(this.name + "愛學(xué)習(xí)");
    }    
}

let stu4 = {
    _name: null, /*類似于java中私有成員變量*/
    get name() {
        console.log("進(jìn)入了get");
        return this._name;
    },
    set name(name) {
        console.log("進(jìn)入了set");
        this._name = name;
    }
}

stu4.name = "小白"
console.log(stu4.name)

let stu = {name:'張三'};
stu.age = 18;					// 添加屬性
delete stu.age;					// 刪除屬性
stu.study = function() {		// 添加方法
    console.log(this.name + "在學(xué)習(xí)");
}

let stu = {_name:null};
Object.defineProperty(stu, "name", {
    get(){
        return this._name;
    },
    set(name){
        this._name = name;
    }
});

public class TestMethod {
    static class Student {
        private String name;
        public Student(String name) {
            this.name = name;
        }
        public void study(Student this, String subject) {
            System.out.println(this.name + "在學(xué)習(xí) " + subject);
        }
    }
    public static void main(String[] args) {
        Student stu = new Student("小明");
        // 下面的代碼，本質(zhì)上是執(zhí)行 study(stu, "java")，因此 this 就是 stu
        stu.study("java"); 
    }
}

function study(subject) {
    console.log(this.name + "在學(xué)習(xí) " + subject)
}

study("js");  // 輸出 在學(xué)習(xí) js

let stu = {
    name:"小白",
    study
}

stu.study('js'); 	// 輸出 小白在學(xué)習(xí) js

let stu = {name:"小黑"};
study.call(stu, "js");	// 輸出 小黑在學(xué)習(xí) js

let stu = {
    name: "小花",
    friends: ["小白","小黑","小明"],
    play() {
        this.friends.forEach(function(e){
            console.log(this.name + "與" + e + "在玩耍");
        });
    }
}
stu.play()

let stu = {
    name: "小花",
    friends: ["小白","小黑","小明"],
    play() {
        this.friends.forEach(e => {
            console.log(this.name + "與" + e + "在玩耍");
        })
    }    
}

let stu = {
    name: "小花",
    friends: ["小白","小黑","小明"],
    play() {
        let me = this;
        this.friends.forEach(function(e){
            console.log(me.name + "與" + e + "在玩耍");
        });
    }
}

let father = {
    f1: '父屬性',
    m1: function() {
        console.log("父方法");
    }
}
let son = Object.create(father);
console.log(son.f1);  // 打印 父屬性
son.m1();			  // 打印 父方法

function cons(f2) {
    // 創(chuàng)建子對象(this), 給子對象提供屬性和方法
    this.f2 = f2;
    this.m2 = function () {
        console.log("子方法");
    }
}
// cons.prototype 就是父對象
cons.prototype.f1 = "父屬性";
cons.prototype.m1 = function() {
    console.log("父方法");
}

let son = new cons("子屬性")

{
    "name":"張三",
    "age":18
}

{
    name:"張三",
    age:18
}

JSON.parse(json字符串);  // 返回js對象
JSON.stringify(js對象);  // 返回json字符串