With the development of Internet technology, front-end technology is also constantly developing and innovating. Vue.js is a popular front-end framework that uses data-driven and component-based ideas to help front-end developers quickly build single-page applications. This article will introduce the basic concepts and usage of the Vue framework.
1. Overview of Vue Framework
Vue.js is a lightweight JavaScript library designed for building user interfaces. It is also called MVVM (data model-view-view). model) framework. The Vue.js core library only focuses on the view layer and can be easily integrated with other third-party libraries or existing projects. Vue.js provides two core features: responsive data binding and composable view components.
2. The core concepts of the Vue framework
1. Data binding
Vue.js adopts a data-driven idea. Modifying data on the interface will directly affect the data. model and vice versa. Vue.js implements data binding by utilizing the Object.defineProperty() method. When a piece of data changes, Vue.js will automatically update the content of the view layer.
2. Template syntax
Template is an important concept in Vue.js. It is a language used to write HTML, which contains the special syntax of Vue.js for Bind data and control logic. Vue.js uses an AST-based compiler to compile templates into rendering functions.
3. Componentization
Vue.js provides a very powerful component system, allowing developers to split a large application into multiple components. Each component contains its own HTML, CSS and JavaScript code and can be nested within other components. Components can effectively achieve code reuse and logical separation, making applications easier to maintain and develop.
3. How to use the Vue framework
1. Install Vue.js
First, we need to install the Vue.js library in the project. The installation can be completed through the npm command, as follows:
npm install vue
2. Create a Vue instance
The Vue instance is an independent, reusable Vue component, which is a JavaScript object. We can use the Vue constructor to create a Vue instance, as shown below:
var vm = new Vue({ //选项 })
3. Templates and template syntax
The templates in Vue.js use some special syntax for Bind data and control logic. These include interpolation expressions, directives, filters, etc.
Interpolation expression
Interpolation expression is used to insert data in the template. The syntax is double curly brackets, as shown below:
<p>{{ message }}</p>
Among them, message is a Vue instance data in.
Directive
Directive is a special HTML attribute used to manipulate the behavior of DOM elements. The syntax of the directive starts with v- and uses an expression in the attribute value. For example:
<button v-on:click="submit">Submit</button>
Among them, the v-on instruction is used to bind a click event, and submit is a method in a Vue instance.
Filter
Filters can be used to process text formatting in templates. It uses the pipe symbol (|) as the delimiter and can be used with interpolation expressions. For example:
<p>{{ message | toUpperCase }}</p>
Among them, toUpperCase is a custom filter used to convert the text in the message to uppercase.
4. Components and composition
Components are an important concept in Vue.js, which represent composable code blocks in the application. A Vue component can contain a template, a data model and some methods. Components can be continuously nested to form a complex application. Creating a component requires two steps:
1) Define a component
Vue.component('my-component', { template: '<p>{{ message }}</p>', data: function() { return { message: 'Hello World!' } } })
Among them, my-component is the name of the component, template and data define the template and data of the component respectively.
2) Using components
When using a custom component in the HTML code of the application, you need to register the component in the Vue instance. For example:
<div id="app"> <my-component></my-component> </div> var vm = new Vue({ el: '#app' })
The above code will render a template from a custom component in the application.
4. Summary
Vue.js is a popular front-end framework that adopts the MVVM model and the idea of component development. It has core features such as responsive data binding, template syntax, and a powerful component system, which can help front-end developers quickly build single-page applications. This article introduces the basic concepts and usage of the Vue framework, and hopes to be helpful to your front-end development work.
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