Skip to main content

The use of v-for directive in Vue

In Vue, a v-for loop is used to get dynamic data, thus creating a dom tree, such as the very common ul>li list. When I need to traverse an array or enumerate an object and display it in a loop, I often use the list rendering instruction v-for. It needs to be used in combination with in or of, as follows. When Vue renders elements, for the sake of efficiency, it will reuse existing elements as much as possible instead of re-rendering. If you don't want this, you can use the key attribute provided by Vue, which allows you to decide whether to reuse elements. Key The value must be unique.

Look directly at the sample code as follows:

   <div id="app">
        <h2>v-for:</h2>
Please enter the value you want to filter(name or age):<input type="text" v-model="inputVal">
        <ul>
            <li v-for="(value,index) of filterPerson">{{value.id}}-{{value.name}}-{{value.age}}</li>
        </ul>
    </div>
    <script>
     Vue.config.productionTip=false;
         var vm = new Vue({
            el: '#app',
            data: {
                inputVal:'',
                num:100,
                person:[
                    {id:1001,name:"aaa",age:18},
                    {id:1002,name:"bbb",age:19},
                    {id:1003,name:"ccc",age:20}
                ],
                filterPerson:[]
            },
            methods: {  
            },
            watch:{
                inputVal:{
               immediate:true,
               handler(value){
                this.filterPerson=this.person.filter((item)=>{
                    return item.name.indexOf(value)!==-1||item.age.toString()===value;
                })
               }
            }
        }
        });
     /*     var vm = new Vue({
            el: '#app',
            data: {
                inputVal:'',
                num:100,
                person:[
                    {id:1001,name:"aaa",age:18},
                    {id:1002,name:"bbb",age:19},
                    {id:1003,name:"ccc",age:20}
                ],  
            },
            methods: {  
            },
            computed:{
                filterPerson(){
                  let afterval=  this.person.filter((item)=>{
        return item.name.indexOf(this.inputVal)!==-1||item.age.toString()===this.inputVal;
                    })
                    return afterval;
                }
            }
        }); */
    </script>

Labels:

Comments

Post a Comment

Popular posts from this blog

favicon.ico 404 Not Found Causes and Solutions

 What is favicon? It is the abbreviation of Favorites Icon. Its function is that in addition to displaying the corresponding title in the browser's favorites, icons can also be used to distinguish different websites. When I encounter this kind of error, I feel very uncomfortable. There is obviously no problem. Why is a 404 error reported? The following is the solution.
Post a Comment
Read more

mapState, mapGetters, mapMutations, mapActions in vuex

 The above four objects are all in the vuex plug-in store, which is often used to store some data shared globally. But I still feel a little uncomfortable when using it, that is, I wrote a lot of repeated prefixes. At this time, these four objects appeared, which solved this pain point very well. mapState is mainly used to manipulate and obtain data, mapGetters is equivalent to computed properties, and mapMutations and mapActions are simplifications of mutation and action. They can be written as both objects and arrays.
Post a Comment
Read more

Destructuring assignment in ES6

 In the past, when we wanted to assign a value to a variable, such as an array type and an object type, to assign a value to a variable, we could only specify the value directly. It is very troublesome to write in this way, but under the ES6 syntax specification, it is allowed to directly extract the required values from arrays and objects according to a certain pattern, and directly assign variables to variables. This method is called Destructuring, which is simple to understand. That is, the left and right sides of the equal sign are equal.
Post a Comment
Read more