一、例子

1、以…结尾

1.1、超过六位

<script>
        //超过六位以...结尾
        var str = "时间有限来不及去惦记心里没有我的人"
        console.log(str.length);
        if(str.length>6){
            var res = str.slice(0,6)+"...";  //var res = str.substr(0,6)+"...";
            console.log(res);
        }
    </script>

1.2、超过三位

<script>
        var arr = [
            "时间有限来",
            "及去惦记心里",
            "及去惦记心里没有我的人",
            "你好"
        ]
        var res = [];
        arr.forEach(item=>{
            if(item.length>3){
                item = item.substr(0,3)+"...";
            }
            res.push(item);
        })
        console.log(res);
    </script>

1.3、map方法实现：

<script>
        var arr = [
                "时间有限来",
                "及去惦记心里",
                "及去惦记心里没有我的人",
                "你好"
            ]
        var res = arr.map(item=>{
            if(item.length>3){
                item = item.substr(0,3)+"...";
            }
            return item
        })
        console.log(res);
    </script>

1.4、把含有“你”的字符串超过三位以…结尾

<input type="text" id="app">
    <script>
         var arr = [
                "时间有限来",
                "及去惦你记心里",
                "及去惦记心里没有我的人",
                "你好"
            ]
       $("#app").keyup(function(event){
           if(event.keyCode == 13){
                var value = $(this).val();
                var res = arr.filter(item=>{
                    return item.includes(value);
                })
                var lists = res.map(item=>{
                    if(item.length>3){
                        item = item.substr(0,3)+"...";
                    }
                    return item;
                })
                console.log(lists);
           }
       })
    </script>

1.5、通过id搜索，最后以…结尾

<input type="text" id="app">
    <script>
        var arr = [
            {id:1001,name:"fslkhlasl"},
            {id:1002,name:"bkhaoiuohf"},
            {id:1003,name:"hiuios"}
        ]
//1.获取input的值
     $("#app").keyup(function (event) {
            if (event.keyCode == 13) {
                var value = $(this).val();
                var res = arr.find(item=>{
                    return item.id == value;
                })
                res.name = res.name +"...";
                var list = [res];
                console.log(list);
            }
        })
    </script>

2、字符串分割数组反转

<script>
        var str = "hello";
        var arr = str.split("") 
        console.log(arr);
        arr.reverse();
        console.log(arr.join(""));
    </script>

3、?key=你&age=18

<script>
        var str = "?key=你&age=18"
        var res = str.slice(1);
        var list = res.split("&");
        console.log(list);
        var key = list[0];
        var age = list[1];
        key = key.split("=")[1];
        age = age.split("=")[1];
        var obj = {
            key,
            age,
        }
        console.log(obj);
    </script>

3.1、”?key=你&age=18&offset=10”

<script>
        var list = [];
        var str = "?key=你&age=18&offset=10";
        //[{key:"你"},{age:18},{offset:10}]
        var arr = str.slice(1).split("&");
        arr.forEach(item=>{
            var res = item.split("=");
            var obj = {};
            obj[res[0]]=res[1];
            list.push(obj);
        })
        console.log(list);
    </script>

3.2、map 方法 “?key=你&age=18&offset=10”

<script>
        var str = "?key=你&age=18&offset=10";
        var arr = str.slice(1).split("&");
        console.log(arr);
        var res = arr.map(item=>{
            var obj = {};
            var list = item.split("=");
            obj[list[0]] = list[1];
            console.log(obj);
            return obj;
        })
        console.log(res);
    </script>

3.3、”https://www.baidu.com?order=hot&cat=你&limit=35&offset=140“

<script>
        var url = "https://www.baidu.com?order=hot&cat=你&limit=35&offset=140";
        var res = url.split("?")[1].split("&");
        console.log(res);
        var obj = {};
        //让数组的每一项中，第一项作为key，第二项作为value
        res.forEach(item=>{
            var list = item.split("=");
             obj[list[0]] = list[1];
        })
        console.log(obj);
    </script>