Vue. js implements data pulling and updating using custom commands. vue. js customizes data pulling and updating.

Vue. js implements data pulling and updating using custom commands. vue. js customizes data pulling and updating.

Preface

The code snippet of this article is located in the single file component of vue, that is. in the file at the end of vue, this article describes only one implementation method. It is neither the only method nor the best method. If you have a better method, leave a message for discussion.

Step 1

First, you must first define the variables:

// App. vue <script> data () {return {// defines getData :{}, // defines the binding value of the custom command ifUpdate: true }}

Step 2

Then, to use ajax, introduce jquery in index.html so that you can use it globally:

// index.html<script type="text/javascript" src="./lib/js/jquery-2.1.1.min.js"></script>

Step 3

Then, a custom command is used to automatically execute the methods in the Custom command after the component is instantiated:

After the component is instantiated, it will immediately start with an initial valueifUpdate This is the first time a custom command is called for a parameter.initData Method, followed by each parameter valueifUpdate It will be called again when it changesinitData The parameter isifUpdate And the old value.

// App. vue <template> // bind custom commands to the page node (select as needed) <div v-initData = "ifUpdate"> </div>

// App. vue <script> // define the custom directive directives: {initData: function (val, oldVal) {if (! Val) {return;} var self = this; $. getJSON ("ajax/test. json ", function (data) {self. vm. getData = data;}); // when the value of ifUpdate is updated to true next time, the above ajax will be used again to obtain the data self. vm. ifUpdate = false ;}}

Use Cases

After the user comments, refresh the Comments List:

After obtaining the comment data for the first timeifUpdate Changefalse

After adding a comment, the user uploads the data to the background andifUpdate Changetrue

Command accordingifUpdate Triggered by changes, passed againajax Pull data from the background

Pull after pullingifUpdate Resetfalse

Summary

The above is all the content of this article. I hope this article will be helpful for you to learn or use vue. js. If you have any questions, please leave a message.