What is an instruction in parsing vue? How to use it?

Vue.js is a popular JavaScript framework that provides an efficient way to build interactive front-end applications. One of Vue's key features are directives. They provide a way to extend the DOM into a canonical state, making it easier to understand, use, and maintain.

This article will introduce directives in Vue.js and demonstrate how they work and how to use them.

What is the command?

Directives are special attributes added to DOM elements in Vue.js. They appear v- prefixed and are then interpreted and compiled in the Vue instance. Directives can be used to add attributes on elements, bind data, set styles, respond to events, and more.

How to use instructions?

To use directives, add them to the elements you want to operate on. The general form of directives is as follows:

<element v-directiveName:argument="value"></element>

where element is the DOM element to which the directive is to be applied, directiveName is the name of the directive, argument is the optional parameter of the instruction, and value is the value of the instruction.

For example, the v-text directive is used to add text to an element, you can use the following syntax:

<p v-text="message"></p>

where message is the text to be added to the p element, which can be in the Vue instance Properties or methods defined in .

Some examples of standard HTML elements with legal directives include:

• a
• abbr
• article
• aside
• audio
• b
• button
• canvas
• code
• div
• em
• footer
• form
• h1 - h6
• header
• hr
• i
• img
• input
• label
• li
• main
• nav
• ol
• p
• pre
• section
• span
• strong
• sub
• sup
• textarea
• ul
• video

Types of directives

There are many types of directives in Vue.js, each directive has a specific function. Some commonly used directives include:

• v-text: Used to add text content to an element.

  <p v-text="message"></p>

• v-html: Used to add HTML content to an element.

  <div v-html="html"></div>

• v-show: Used to switch between elements based on the value of an expression.

  <div v-show="isVisible"></div>

• v-if: Used to add or remove elements based on the value of an expression.

  <div v-if="showElement"></div>

• v-for: Used to iterate over an array or object and add elements for each item or property.

  <ul>
    <li v-for="item in items"> {{ item }} </li>
  </ul>

• v-on: Used to listen to DOM events and execute methods when triggered.

  <button v-on:click="onButtonClick">Click me</button>

• v-bind: Used to bind attributes to elements.

  <img v-bind:src="imageUrl">

Summary

Directives in Vue.js are a powerful feature that help you manage and extend the DOM more easily. This article covers the basics of how to apply directives in Vue.js, as well as the types of directives and how to use them. By mastering this knowledge, you can create web applications that are smoother, more flexible, and easier to maintain.

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