How vue gets data

Vue is a popular front-end framework that places great emphasis on data processing and management. In Vue, how to obtain data is very important, which directly affects the performance and user experience of the application. This article will introduce several ways to obtain data in Vue.

1. Simple data binding

Vue’s simple data binding is the most basic way to obtain data. It can bind data to DOM elements, and when the data changes, the corresponding DOM elements will be automatically updated. Vue's data binding method is very simple. You only need to declare the data in the instance, and then bind the data in the DOM element you want to use.

For example:

<div id="app">
  <p>{{ message }}</p>
</div>

<script>
  var app = new Vue({
    el: '#app',
    data: {
      message: 'Hello, Vue!'
    }
  })
</script>

In the above code, we declare a message data in the Vue instance, and use double bracket syntax in the DOM element to bind it to a p tag .

2. Computed properties

Vue's calculated properties are an advanced way to obtain data. It can calculate a new value based on existing data and store it. return. Vue’s computed properties can reduce logic in templates, making them clearer and more readable. Computed properties can also cache calculation results to avoid unnecessary repeated calculations.

For example:

<div id="app">
  <p>{{ reversedMessage }}</p>
</div>

<script>
  var app = new Vue({
    el: '#app',
    data: {
      message: 'Hello, Vue!'
    },
    computed: {
      reversedMessage: function () {
        return this.message.split('').reverse().join('')
      }
    }
  })
</script>

In the above code, we declare a calculated property reversedMessage in the Vue instance, which reverses the message data by using the split() and reverse() methods.

3. Listener

Vue's listener is an advanced way to obtain data. It can monitor changes in a certain data and execute corresponding actions when the data changes. operate. Vue's listener can help us implement some complex business logic, such as data linkage, etc.

For example:

<div id="app">
  <input v-model="message">
  <p>{{ messageLength }}</p>
</div>

<script>
  var app = new Vue({
    el: '#app',
    data: {
      message: 'Hello, Vue!'
    },
    watch: {
      message: function () {
        this.messageLength = this.message.length;
      }
    },
    created: function () {
      this.messageLength = this.message.length;
    }
  })
</script>

In the above code, we use a listener in the Vue instance to listen for changes in message data, update the messageLength data when it changes, and bind it to on a p tag.

4. Life cycle hook

Vue’s life cycle hook is an advanced way to obtain data. It can perform corresponding operations at various life cycle stages of the component, including retrieve data. Vue's lifecycle hooks are very flexible and can be freely configured according to different business scenarios.

For example:

<div id="app">
  <p>{{ message }}</p>
</div>

<script>
  var app = new Vue({
    el: '#app',
    data: {
      message: ''
    },
    created: function () {
      this.getMessage();
    },
    methods: {
      getMessage: function () {
        // 通过 Ajax 获取数据
        // 然后更新 message 数据
      }
    }
  })
</script>

In the above code, we use the life cycle hook created in the Vue instance to obtain data. This ensures that the operation of obtaining data is executed immediately after the instance is created. .

Summary

There are many ways to obtain data in Vue, and we can choose the appropriate method according to different business scenarios. Simple data binding is the most basic method and is suitable for simple application scenarios; calculated properties can help us calculate complex logic; listeners can monitor changes in certain data and perform corresponding operations when they change; life cycle hooks Corresponding operations can be performed at various life cycle stages of the component, including obtaining data. Mastering these methods can help us better process and manage data, and improve application performance and user experience.

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