A deep dive into the reactive process with Vue.js

Vue.js is a popular JavaScript framework that allows you to build responsive user interfaces. At its core, Vue.js is a reactive system that allows you to create data models and automatically update views when the data changes. In this article, we’ll take a deep dive into the reactive process of Vue.js.

Vue.js Responsive Process

1. Data Responsive

In Vue.js, you can use new Vue({…}) to Create a Vue instance. Vue instances have a data property that contains the JavaScript object used as the data model. These data properties will become part of Vue.js’ reactive system.

Vue.js automatically updates the view when you change the properties of the object. To understand how Vue.js does this, we need to understand how data is reactive.

When you pass an object as a data property to the Vue constructor, Vue.js iterates through the entire object and converts each property into a getter and setter using the Object.defineProperty() method. This method allows Vue.js to use "interceptors" to update the view when the data changes.

This automated data responsiveness is a key feature of Vue.js. It makes Vue.js development easier, simpler and faster.

For example, the following code creates a JavaScript object containing the message property and passes it to the Vue constructor as the data property:

new Vue({
  data: {
    message: 'Hello world!',
  }
});

When you change the message property, Vue.js The view will be updated. For example, the following code will change the value of the message attribute:

vm.message = 'Hello Vue!';

2. Templates and Rendering Functions

Vue.js uses templates and rendering functions to create views. A template is some HTML code that includes placeholders, directives, and expressions for displaying data from the Vue.js data model. The render function is a JavaScript function that converts data into HTML. Vue.js combines data and templates to create HTML.

Vue.js has a very powerful template system that allows you to quickly create complex views. The following is a basic Vue.js template:

<div>
  <h1 id="message">{{ message }}</h1>
  <input>
</div>

This template contains a div element that has an id attribute with the value "app". It also includes an h1 element and an input element. The h1 element contains a template expression {{ message }}, which is used to display the value of the message attribute in the Vue.js data model. The input element uses the v-model directive to bind the input to the message attribute.

When you enter text in the input element, Vue.js will automatically update the value of the message attribute and update the new value to the h1 element in the template.

Vue.js also supports render functions, which are a more flexible way to create views. The render function accepts data as input and generates an HTML fragment as output. The following is a simple Vue.js rendering function:

new Vue({
  render: function (createElement) {
    return createElement('div', {
      attrs: { id: 'app' }
    }, [
      createElement('h1', this.message),
      createElement('input', {
        domProps: {
          value: this.message
        },
        on: {
          input: (event) => {
            this.message = event.target.value
          }
        }
      })
    ])
  }
})

3. Computed properties and listeners

Vue.js’s computed properties and listeners provide a A method for updating data when it changes. A computed property is a property that depends on other data, while a listener is a method that performs an action when specific data changes.

Computed properties are very commonly used in Vue.js. They allow you to encapsulate data logic in a Vue.js instance and provide responsive updates. The following is a simple Vue.js computed property:

new Vue({
  data: {
    firstName: 'John',
    lastName: 'Doe'
  },
  computed: {
    fullName: function () {
      return this.firstName + ' ' + this.lastName
    }
  }
})

This example creates a Vue.js instance and defines two properties using the data attribute: firstName and lastName. The instance also creates a fullName computed property using the computed property, which returns the combined string of firstName and lastName.

When you change the firstName or lastName property, the computed property will be updated automatically, and the fullName property will be updated, thus updating the data in the view.

Listeners are also useful in Vue.js. They allow you to perform some actions after specific data changes. For example, the following is a Vue.js listener:

new Vue({
  data: {
    firstName: 'John',
    lastName: 'Doe',
    fullName: ''
  },
  watch: {
    firstName: function (val) {
      this.fullName = val + ' ' + this.lastName
    },
    lastName: function (val) {
      this.fullName = this.firstName + ' ' + val
    }
  }
})

This example creates a Vue.js instance and defines three properties using the data attribute: firstName, lastName, and fullName. The instance also creates two listeners using the watch attribute, one for the firstName and lastName properties.

When you change the firstName or lastName property, the corresponding listener function will automatically run and update the fullName property and update the data in the view.

Conclusion

Vue.js’s reactive system makes developing responsive applications easier and simpler. In Vue.js, data and views are completely separated, which makes it easier to add new functionality to your application. Features such as Vue.js's data reactivity, template and render functions, computed properties, and listeners make Vue.js ideal for building effective and efficient applications.

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