Analysis of created function examples in Vue documentation

Vue.js is a modern front-end framework that adopts some common programming concepts such as components and data binding. In the Vue.js documentation, a very commonly used function is the created function. This article will do an example analysis of the created function in the Vue document.

created function

The created function in Vue.js is a hook function called when a Vue instance is created. It can be used to initialize some data and is called when an instance is completely created. . This function can access some data and methods in the Vue instance, including computed properties and methods.

The syntax of the created function is as follows:

new Vue({
  created: function () {
    // ...
  }
})

When creating a Vue instance, you can add the created function to the options of the Vue instance. When this Vue instance is created, it automatically calls this function.

Example Analysis

Suppose we now have a simple Vue component, which is used to render a picture and a piece of text. We can define the template and data of this component as follows:

<template>
  <div>
    <img :src="image">
    <p>{{text}}</p>
  </div>
</template>

<script>
export default {
  data () {
    return {
      image: '',
      text: ''
    }
  }
}
</script>

Before this component is created and rendered, we need to use an HTTP request to obtain the URL and text content of the image, and then save them to the component respectively. in the image and text data. This process can be implemented in the created function. The following is a created function that implements this function:

export default {
  data () {
    return {
      image: '',
      text: ''
    }
  },
  created () {
    axios.get('https://example.com/api/data').then(response => {
      this.image = response.data.imageURL
      this.text = response.data.content
    })
  }
}

In this function, first we use a get method of the axios library, which will obtain some data from the specified URL. When the get method successfully obtains the data, we save the image URL and text content to the image and text data of the component.

Using the created function can ensure that the data required by the component has been obtained before the component is completely created. And because the created function is executed when the Vue instance is created, it can perform any necessary data initialization before the component is rendered.

Summary

In the Vue.js documentation, the created function is a commonly used function. It can be automatically called when a Vue instance is created to initialize some data. We can use this function to obtain the necessary data before the component is rendered, making the component display more complete and perfect.

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