Javascript 设计模式

//状态模式
var status  = {
    statusArr:[],
    on(state){
         this.statusArr.push(state);
         return this;
    },
    fire(){
    
        this.statusArr.forEach((v,k)=>{
            this.actionArr[v]();
        })
    },
    actionArr:{
        jump:function(){
            console.log('jump');
        },
        run:function(){
            console.log('run');
        },
        fire:function(){
            console.log('fire');
        },
    }
}

status.on('run').on('jump').fire();


//观察者模式

//观察者模式
//抽奖 每转一圈，速度减慢
var obs = {
   
    //监听队列
    fallback:{

    },
    //注册监听
    on:function(name,fn){
        this.fallback[name] = fn;
    },
    //触发监听
    fire:function(name){
         this.fallback[name]();

    },
    //删除监听
    delete:function(name){
        this.fallback[name] = null
    }
   
    
}

obs.on('done',()=>{
    console.log('well done');
})

obs.fire('done')



//策略模式
function calc(type,a,b){
    let calc = {
        add:function(a,b){
            return a+b;
        },
        declare:function(a,b){
            return a-b;
        }

    }
    return  calc[type](a,b);
}

let res = calc('declare',3,5);
let res2 = calc('add',3,5);
console.log(res,res2);



//命令模式 只关心命令，不用关心别的
var cm = {
    target:'dom1',
    data:[{pic:'xxx.png',title:'xxx'}],
    type:'left'
}
function command(){
    var __html = '';
    var create = function(styleObj,arr){
        arr.forEach((v,k) => {
            __html = ``;//拼接成显示的 html 字符串
        });
    }
    var display = function(dom){
        var dom = document.getElementById(dom);
        dom.innerHtml = __html;
    }
    var excute = function(command){
        var calcer = {
            left:'float:left;',
            top:''
        }    
        create(calcer(command.type),command.data);
        display(command.target);
    }
    return {
        excute
    }
}

command(cm);


//迭代器模式
let dector = function(){}
dector.has = (obj,value)=>{
    let res = false;
    for(let item in obj){
        if(obj[item] === value){
            res =  true;
        }

    }

    return res;
}

let s = dector.has({a:1},1)
console.log(s);


//惰性模式
let b = 100;
var a = (()=>{
    if(b===100){
       return a = ()=>{
            console.log('a')
        }
    }else{
       return  a = ()=>{
            console.log('b')
        }
    }
})()

 
a()