How to use the asynchronous request function in the Vue documentation

Vue.js is a popular front-end JavaScript framework that provides a way to build user interfaces in applications. In the Vue.js documentation, we can find a lot of useful information, especially about how to use asynchronous request functions.

Asynchronous request functions are a way to perform asynchronous tasks in an application. They are used to get data from the server, process input, validate forms, etc. Generally, asynchronous request functions need to be used in conjunction with JavaScript language features such as Promise, async and await.

In Vue.js, we can use third-party libraries such as axios or fetch to implement asynchronous requests. axios is an HTTP client that allows us to easily send asynchronous requests and handle responses. fetch is also an HTTP client, which is implemented using the JavaScript native Fetch API.

To use axios in Vue.js, you first need to install axios in the project:

npm install axios --save

After the installation is complete, the sample code for using axios in the component of Vue.js is as follows:

import axios from 'axios'

export default {
  data () {
    return {
      posts: []
    }
  },
  mounted () {
    axios.get('https://jsonplaceholder.typicode.com/posts').then(response => {
      this.posts = response.data
    })
  }
}

In the above code, we use the get method of axios to send a request to https://jsonplaceholder.typicode.com/posts, and assign the response data to the posts attribute of the component after the request is successful.

In addition to the get method, axios also provides other request methods such as post, put, delete, etc., which can be used according to actual needs.

On the other hand, the sample code for using fetch to implement asynchronous requests is as follows:

export default {
  data () {
    return {
      posts: []
    }
  },
  mounted () {
    fetch('https://jsonplaceholder.typicode.com/posts')
      .then(response => response.json())
      .then(data => {
        this.posts = data
      })
  }
}

In this case, we use the fetch method to send the request, and use the then method to process the response, and send the response data Parse it into JSON format and assign it to the posts attribute of the component.

When using axios or fetch, we can also use async and await syntax to handle asynchronous operations. This makes the code more readable and concise. For example, rewrite the above axios sample code using async and await as follows:

async mounted () {
  const response = await axios.get('https://jsonplaceholder.typicode.com/posts')
  this.posts = response.data
}

In the above code, we use async and await syntax to simplify the processing of asynchronous operations.

It should be noted that when using axios or fetch to make asynchronous requests, you need to take into account the error or failure of the request. In order to handle this situation, you can use try/catch syntax to handle exceptions in axios. The sample code is as follows:

async mounted () {
  try {
    const response = await axios.get('https://jsonplaceholder.typicode.com/posts')
    this.posts = response.data
  } catch (error) {
    console.log(error)
  }
}

In fetch, we can use the catch method to handle exceptions:

mounted () {
  fetch('https://jsonplaceholder.typicode.com/posts')
    .then(response => response.json())
    .then(data => {
      this.posts = data
    })
    .catch(error => {
      console.log(error)
    })
}

Total Generally speaking, the Vue.js documentation provides many useful methods to use asynchronous request functions. We can choose a suitable way to handle asynchronous tasks according to actual needs.

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