How to use the construction method in vue

Vue is a popular JavaScript framework that provides many useful features, including Vue components. Vue components allow you to break your application into reusable, smaller parts. In this article, we will cover the basics of Vue components and how to use them.

Basics of Vue components

Vue components are part of the Vue framework and are used to represent reusable, smaller parts of an application. Components can contain HTML, CSS, and JavaScript, and can be used multiple times within an application. This makes components very useful when developing large applications because you can focus each component on its own task without having to mash the entire application together.

To create a Vue component, you can use the Vue.component() method. This method requires two parameters, the component name and the component options object. Component names must be lowercase strings and can contain only hyphens, numbers, and letters. The component options object must contain a template element, which contains the component's HTML code.

The following is a simple Vue component example:

Vue.component('my-component', {
  template: '<div>这是我的组件</div>'
});

To use this component in your application, reference it in the Vue instance:

new Vue({
  el: '#app',
  template: '<my-component></my-component>'
});

In this example , we add my component to the template of the Vue instance. Now, when the Vue instance is instantiated, it will display this component on the page.

How to use Vue components

There are many ways to use Vue components. In the following sections, we will introduce some commonly used methods.

Props

Communication between components is an important function of Vue components. When the parent component needs to pass data to the child component, you can use the props attribute. This is done by defining an array of props in the child component.

The following is an example of a subcomponent showing how to use props attributes:

Vue.component('child-component', {
  props: ['message'],
  template: '<div>{{ message }}</div>'
});

new Vue({
  el: '#app',
  data: {
    parentMsg: '来自父亲的消息'
  }
});

In this example, we define a props attribute named "Message" and add it in the subcomponent's template cite it in. In the parent component, we define a data object called parentMsg and set its value to 'Message from parent'. Now, we can use the child component in the parent component and pass the parentMsg as a prop:

<div id="app">
  <child-component :message="parentMsg"></child-component>
</div>

In this example, we have used the v-bind directive to bind the parentMsg as the message property of the child component. Now the child component will display the message from the parent component.

Emit

Emit allows child components to pass data to parent components. Child components can use a special $emit method, which triggers a custom event on the parent component.

The following is an example that shows how to use emit to implement a child component to pass data to a parent component:

Vue.component('child-component', {
  template: '<button v-on:click="emitEvent">发送事件</button>',
  methods: {
    emitEvent: function() {
      this.$emit('my-event', '这是我的消息');
    }
  }
});

new Vue({
  el: '#app',
  data: {
    parentMsg: ''
  },
  methods: {
    handleEvent: function(msg) {
      this.parentMsg = msg;
    }
  }
});

In this example, the child component contains a button that sends an event, and when clicked Use the $emit method to trigger the 'my-event' event when pressing the button. In the parent component, we define a method called handleEvent and bind it to the 'my-event' event. When the component triggers this event, the handleEvent method will be called and receive the message passed by the child component.

<div id="app">
  <child-component v-on:my-event="handleEvent"></child-component>
  <p>{{ parentMsg }}</p>
</div>

In this example, we bind the handleEvent method to the 'my-event' event and display the value of parentMsg on the page. Now, when the child component clicks the button and the 'my-event' event is triggered, the handleEvent method will be called and the message passed by the child component will be stored in the parentMsg variable.

Slot

Slot is another important function of the Vue component. It allows a parent component to pass HTML code to a child component and include it in the child component's template.

The following is an example that shows how to use the Slot function to pass HTML code from a parent component to a child component:

Vue.component('child-component', {
  template: '<div><slot></slot></div>'
});

new Vue({
  el: '#app'
});

In this example, we use 58cb293b8600657fad49ec2c8d37b472 in the child component template. element. This element will display the corresponding HTML code in the child component. Now, we can use the 6520631531c208a38051e59cee36c278 tag in the parent component and enter the HTML code in the tag:

<div id="app">
  <child-component>
    <h1>这是一级标题</h1>
    <p>这是一段文本</p>
  </child-component>
</div>

In this example, the HTML code of the parent component will be included in the template of the child component and displayed on the page.

Scoped Slots

Scoped Slots is an advanced slot feature that allows you to pass data to child components instead of HTML code. This is very useful as it allows you to reuse components in different contexts.

The following is an example that shows how to use the Scoped Slots feature to pass data from a parent component to a child component:

Vue.component('child-component', {
  template: '<div><slot v-bind:user="user"></slot></div>',
  data: function() {
    return {
      user: {
        name: '张三',
        age: 20
      }
    }
  }
});

new Vue({
  el: '#app',
  methods: {
    getUser: function(name, age) {
      alert(name + ' ' + age);
    }
  }
});

In this example, we use 58cb293b8600657fad49ec2c8d37b472 in the child component template. element and pass the user object to it. In the parent component, we define a method called getUser and bind it to the d477f9ce7bf77f53fbcf36bec1b69b7a element in the child component.

<div id="app">
  <child-component>
    <template v-slot:default="slotProps">
      <button v-on:click="getUser(slotProps.user.name, slotProps.user.age)">获取用户信息</button>
    </template>
  </child-component>
</div>

In this example, we use the v-slot directive to bind the user data to the child component's d477f9ce7bf77f53fbcf36bec1b69b7a element, and use the v-on directive and getUser method on the button. Now, when the button is clicked, the parent component will call the getUser method and pass it the user data passed by the child component as a parameter.

Conclusion

Vue components are very useful features that allow you to break your application into reusable, smaller parts. In this article, we introduce the basics of Vue components and some common usage methods, including props, emit, Slots and Scoped Slots. I hope these methods can help you better use Vue component functions and improve the efficiency of your application development.

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