示例

   var arr =[
            {
                name:"lisi",
                age:18,
                likes:["lol","足球"],
                alikes:["音乐","电影"],
                sex:"male"
            },
            {
                name:"王五",
                age:17,
                likes:["ol","篮球"],
                alikes:["函数","事件"],
                sex:"male"
            },
            {
                name:"张三",
                age:165,
                likes:["lo22","足球1"],
                alikes:["音乐2","电影3"],
                sex:"male"
            },
        ]
       var res = [];
       for(var i =0;i<arr.length;i++){
        //    console.log(arr[i])
           var name = arr[i].name;
           var age = arr[i].age;
           var likes = arr[i].likes.concat(arr[i].alikes);
           var alikes = arr[i].alikes.concat(arr[i].alikes);
           res.push(
               {
                   name:name,
                   age:age,
                   likes:likes
               }
           )
       }
       console.log(res)

示例2

es6方法
 var arr =[
            {
                name:"lisi",
                age:18,
                likes:["lol","足球"],
                alikes:["音乐","电影"],
                sex:"male"
            },
            {
                name:"王五",
                age:17,
                likes:["ol","篮球"],
                alikes:["函数","事件"],
                sex:"male"
            },
            {
                name:"张三",
                age:165,
                likes:["lo22","足球1"],
                alikes:["音乐2","电影3"],
                sex:"male"
            },
        ]
            var res = [];
            for(var i =0;i<arr.length;i++){
                //解构
                var {name,age,likes,alikes} = arr[i];
                likes.push(...alikes);
                //键和值相同只用写一个
                var obj={
                    name,
                    age,
                    likes
                }
                res.push(obj);
            }
            console.log(res)

数组中搜索值进行排序,至于顶部

  //让数组中被搜索的值，至于顶部
        var arr =["html","css","js","vue","react"]
       $("#app").keyup(function(event){
        if(event.keyCode ==13){
                /*将值添加到一个数组里面去*/
            var value = $(this).val();
            if(arr.indexOf(value)!=-1){
                console.log(value)
                var index = arr.indexOf(value)
               arr.splice(index,1);
               arr.unshift(value);
               console.log(arr)
            }
        }
        })

字符串请求模板示例

  var arr = [
            {
                imgUrl:"https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fimg1.doubanio.com%2Fview%2Fthing_review%2Fl%2Fpublic%2Fp6346199.jpg&refer=http%3A%2F%2Fimg1.doubanio.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1636337497&t=5cf8473b04e7343e539e7d8d4461afbf",
                name:"cheng",
                age:19
            },{
                imgUrl:"https://gss0.baidu.com/70cFfyinKgQFm2e88IuM_a/baike/pic/item/0e2442a7d933c8952e6a4f65d81373f08202009c.jpg",
                name:"lisi",
                age:18
            }
        ]
        var res = [];
        for(var i=0;i<arr.length;i++){
            //console.log(arr[i])
            var {imgUrl,name,age} = arr[i];
            var template = `
            <div class="item">
                <p>${name}<p>
                    <img src="${imgUrl}"/>
                    <p>${age}</p>
                    </div>
            `
                    console.log(template)
                    $("body").prepend(template)
        }

获取id下标的值

 <input type="text" id="app">
    <script>
        var arr = [
            {name:"李四",id:1001},
            {name:"王四",id:1002},
            {name:"张四",id:1003},
            {name:"赵四",id:1004},
        ]
        var app = document.getElementById("app")
        app.onkeydown = function(event){
            if(event.keyCode ===13){
            //console.log(this.value)
            var id = Number(this.value);
            //获取id的下标值
            //console.log(id);
            var index = arr.findIndex(item=>{
                return item.id ==id;
            })
            arr.splice(index,1);
            console.log(arr)
            }
        }

获取键盘输入框的下标数字

 <input type="text" id="app">
    <script>
        var keyword = "李"
          var students = [
            {name:"李四",age:"18岁"},
            {name:"李二",age:"11岁"},
            {name:"李五",age:"19岁"},
            {name:"王四",age:"22.5岁"},
        ]
        var app = document.getElementById("app")
        app.onkeydown = function(event){
            if(event.keyCode ===13){
                //获取键盘输入框的下标数字
          var keyCode = this.value;
          console.log(keyword)
          var res = students.filter(item=>{
              return item.name.includes(keyword)
          })
          console.log(res)
            }
        }

遍历方法

  //for in
        var arr = ["html","css","js"];
        for(var key in arr){
            console.log(key)//key获取的是数组的下标
            //console.log(arr[key])
        }
        var obj = {
            name:"list",
            age:18
        }
        for(var k in obj){
            console.log(obj[k])
        }

reduce方法

  var arr = [{
            name:"肯德基",price:100,distance:100,num:2
            },
            {
            name:"必胜客",price:200,distance:50,num:1
            },
            {
            name:"华莱士",price:50,distance:1000,num:5   
            }
    ]
    var sum = arr.reduce(function(a,b){
        console.log(a);
        console.log(b);
    })

选择示例option

 <select id="mySelect">
        <option value="price">低价优先</option>
        <option value="distance">距离优先</option>
    </select>
    <script>
          var arr = [{
            name:"肯德基",price:100,distance:100
            },
            {
            name:"必胜客",price:200,distance:50
            },
            {
            name:"华莱士",price:50,distance:1000   
            }
    ]
    var mySelect = document.getElementById("mySelect");
    //console.log(mySelect)
    mySelect.onchange = function(){
        console.log(this.value);
       var value = this.value;
       arr.sort(function(a,b){
           return a[value]-b[value];
       })
        console.log(arr)
    }

根据价格升序排序

var arr = [{
            name:"肯德基",price:100,distance:100
            },
            {
            name:"必胜客",price:200,distance:50
            },
            {
            name:"华莱士",price:50,distance:1000   
            }
    ]
        //根据价格升序
        arr.sort(function(a,b){
            return a.price-b.price;
        })
        console.log(arr)
        // 根据距离进行降序
        arr.sort(function(a,b){
            return b.distance-a.distance
        })
        console.log(arr)

sort方法

 var arr = [12,3,5,11,1];
        console.log(arr.sort())
        var newArr = arr.sort(function(a,b){
            return a-b;
        })
        var c = [12,45,2,3,5];
        var xjj = c.sort(function(a,b){
            return b-a;
        })
        console.log(newArr)
        console.log(xjj)

join方法连接

  <div id="app"></div>
    <script>
        var dates = ["2019","03","09"]
      var str = dates.join("-");
      console.log(str)
      var app = document.getElementById("app")
      app.innerHTML = str;

casts打印在css样式中的方法

 <p id="app"></p>
    <script>
        var directs = [
            {name:"吴京",id:1001},
            {name:"章子怡",id:1002},
            {name:"徐峥",id:1003}
        ]
        var arr = [];
        for(var i = 0;i<directs.length;i++){
            console.log(directs[i].name)
            arr.push(directs[i].name)
        }
        console.log(arr)
        var str = arr.join("/")
        console.log(str)
        var app = document.getElementById("app");
        app.innerHTML = str;