Detailed explanation of components and templates of Vue.js-JS Tutorial-php.cn

Detailed explanation of components and templates of Vue.js

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Release： 2018-01-20 09:46:43

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Instructions are an important feature in Vue.js. They mainly provide a mechanism to map data changes to DOM behaviors. Let me share with you the components and templates of Vue.js through this article. Friends who need it can refer to it. I hope it can help everyone.

Abstract:

Directive is an important feature in Vue.js. It mainly provides a mechanism to map data changes to DOM behavior. Then changes in cross-data are mapped to DOM behaviors. Vue.js is driven by data, so we will not directly modify the DOM structure, and there will be no occurrences like $('ul').append('

one< /li>') such an operation, when the data changes, the instruction will modify the DOM with a set operation, so that you can only focus on the changes in the data without having to manage the changes and status of the DOM,

Vue’s built-in instructions

1. v-bind

v-bind is mainly used to bind DOM element attributes (attributes),

is the actual value of the element attribute It is provided by the data attribute in the vm instance.

For example:

<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Vue的指令</title>
  <script src="../vue.js"></script>
</head>
<body>
<!-- HTML模版 -->
<p id="demo">
  <span v-bind:cutomId="id">{{message}}</span>
</p>
<script>
  //数据
  let obj ={
    message:"Hello World",
    id:'123'
  };
 //声明式渲染
  var vm = new Vue({
    el:'#demo',
    data:obj  });
</script>
</body>
</html>

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v-bind can be abbreviated as ":",

The above example can be abbreviated as

The implementation effect is as follows:

2. v-on

Bind event listener, abbreviated as @.

We also used it yesterday, let’s abbreviate it to see the effect

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Vue的指令</title>
  <script src="../vue.js"></script>
</head>
<body>
  <!-- HTML模版 -->
  <p id="demo">
    <span @click="clickHandle">{{message}}</span>
  </p>
  <script>
    //数据
    let obj = {
      message:"hello Vue"
    };
    //声明式渲染
    var vm = new Vue({
      el:"#demo",
      data:obj,
      methods:{
        clickHandle(){
            alert("click")
            }
      }
    });
  </script>
</body>
</html>

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The effect is as follows:

3.v-html

v-html, the parameter type is string,

is used to update innerHTML,

The accepted string will not be compiled and other operations,

according to ordinary HTML Processing

The code is as follows

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Vue的指令</title>
  <script src="../vue.js"></script>
</head>
<body>
<!-- HTML模版 -->
<p id="demo" v-html="HTML"></p>
<script>
  //数据
  let obj = {
    HTML:"<p>Hello World</p>"
  };
  var vm = new Vue({
    el:"#demo",
    data:obj  })
</script>
</body>
</html>

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The effect is as follows

For more built-in instructions, please check the official website: Vue.js instructions

Template

html template

Based on DOM templates, the templates are parsable and valid html

Interpolation

Text: use "Mustache" syntax (Double braces) {{value}}

Function: Replace the attribute value on the instance,

When the value changes, the interpolation content will be automatically updated

Native html: Double curly braces output text and will not parse html

Attributes: Use v-bind for binding, which can respond to changes

Use JavaScript expressions: you can write simple expressions

String template

template string

The attribute of the template option object

The template will replace the hanging element. Content hanging from the element will be ignored.

The code is as follows

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>template模板</title>
  <script src="../vue.js"></script>
</head>
<body>
  <!--HTML模板-->
  <p id="demo"></p>
  <script>
    //数据
    let obj = {
      html:"<p>String</p>",
      abc:1
    };
    var str = "<p>Hello</p>";
    var vm = new Vue({
      el:"#demo",
      data:obj,
      template:str    })
  </script>
</body>
</html>

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Have you noticed any surprising changes?

## There can only be one root node

Write the html structure in a pair of script tags and set type="X-template"

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>template模板</title>
  <script src="../vue.js"></script>
</head>
<body>
  <!--HTML模板-->
  <p id="demo">
    <span>vue</span>
  </p>
  <script type="x-template" id="temp">
    <p>
      Hello,{{abc}},
      <span>sunday</span>
    </p>
  </script>
  <script>
    //数据
    let obj = {
      html:"<p>String</p>",
      abc:1
    };
    var vm = new Vue({
      el:"#demo",
      data:obj,
      template:"#temp"
    });
  </script>
</body>
</html>

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to achieve the following effect:

is written in the script tag , is still quite limited,

If other files also have this structure,

this cannot be reused.

Template render function

render function

Attributes of render option object

createElement(tag name, {data object}, [child element]);

The sub-element is text or array

Let’s use a piece of code to demonstrate

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>render函数</title>
  <script src="../vue.js"></script>
  <style type="text/css">
    .bg{
      background: #ee0000;
    }
  </style>
</head>
<body>
  <p id="demo"></p>
  <script>
    //数据
    let obj = {
    };
    var vm = new Vue({
      el:"#demo",
      data:obj,
      render(createElement){
        return createElement(
          //元素名
          "ul",
          //数据对象
          {
            class:{
              bg:true
            }
           },
          //子元素
          [
            createElement("li",1),
            createElement("li",2),
            createElement("li",3)
          ]
        );
      }
    })
  </script>
</body>
</html>

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The effect is as follows

About For data object attributes, please refer to the examples on the official website.

Related recommendations:

Vue.js component communication example sharing

About communication issues in Vue.js components

What is a Vue.js component? Summary of Vue.js component usage

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