Vue.js

Vue.js

Original author(s)	Evan You
Initial release	February 2014 (2014-02)
Stable release	2.2.6 / March 27, 2017 (2017-03-27)
Repository	github.com/vuejs/core
Written in	JavaScript
Platform	Cross-platform
Size	76 KB production 240 KB development
Type	JavaScript library
License	MIT License
Website	vuejs.org

Vue.js (commonly referred to as Vue; pronounced /vjuː/, like view) is an open-source progressive JavaScript framework for building user interfaces. Integration into projects that use other JavaScript libraries is made easy with Vue because it is designed to be incrementally adoptable. Also, Vue is a capable web application framework that is able to power advanced single-page applications.

According to a 2016 JavaScript survey, Vue has an 89% developer satisfaction rating. Vue accumulates around 80 GitHub stars per day, and is the 14th most starred project on GitHub of all time.

Overview

Vue.js is a popular JavaScript front-end framework that was built to organize and simplify web development.

It serves as V and lightly the C in an MVC architecture by allowing users to view live data updates and interact with the data through component specific methods (much like a controller).

The project focuses on making ideas in web UI development (components, declarative UI, hot-reloading, time-travel debugging, etc.) more approachable. It attempts to be less opinionated and thus easier for developers to pick up.

Less opinionated allows for progressive adoptable: Vue.js core is a drop-in library that can be used in existing pages. It can be used in existing projects to add simple interactivity, or to replace jQuery and other templating languages and frameworks entirely. Sister libraries can allow Vue to be the base of the entire front end architecture.

History

Vue was created by Evan You after working for Google on AngularJS. You later summed up his thought process, "I figured, what if I could just extract the part that I really liked about Angular and build something really lightweight without all the extra concepts involved?"

Vue was originally released in February 2014 by Evan You. The project was posted on Hacker News, Echo JS, and the /r/javascript subreddit the day of its initial release. Within one day the project reached the frontpage of all three sites.

More recently Vue was featured as a Rising star in GitHub having gained the most stars of any Open Source Project on the popular website. It recently clocked 2,793 Watchers, 48,505 Stars 6,340 Forks which makes it among the most popular open source projects on GitHub in general having far surpassed other popular libraries such as Backbone.js (26,178) Angular 2 (22,471) or even jQuery (44,104) .

Features

Templates

Vue uses an HTML-based template syntax that allows you to declaratively bind the rendered DOM to the underlying Vue instance’s data. All Vue templates are valid HTML that can be parsed by spec-compliant browsers and HTML parsers. Under the hood, Vue compiles the templates into Virtual DOM render functions. Combined with the reactivity system, Vue is able to intelligently figure out the minimal amount of components to re-render and apply the minimal amount of DOM manipulations when the app state changes.

In Vue, you can use the template syntax or choose to directly write render functions using JSX. In order to do so just replace the template option with a render function. Render functions open up possibilities for powerful component-based patterns — for example, the new transition system is now completely component-based, using render functions internally.

Reactivity

One of Vue’s most distinct features is the unobtrusive reactivity system. Models are just plain JavaScript objects. When you modify them, the view updates. It makes state management very simple and intuitive. Vue provides optimized re-rendering out of the box without you having to do anything. Each component keeps track of its reactive dependencies during its render, so the system knows precisely when to re-render, and which components to re-render.

Components

Components are one of the most powerful features of Vue. In a large application, it is necessary to divide the whole app into small, self-contained, and often reusable components to make development manageable. Components extend basic HTML elements to encapsulate reusable code. At a high level, components are custom elements that Vue’s compiler attaches behavior to. In Vue, a component is essentially a Vue instance with pre-defined options. The code snippet below contains an example of a Vue component. The component presents a button and prints of the number of times the button is clicked :

Vue.component('buttonclicked', {
  props: ["initial_count"],
  data: function() {var q = {"count": 0}; return q;} ,
  template: '<button v-on:click="onclick">Clicked {{count}} times</button>'
  ,
  methods: {
    "onclick": function() {
        this.count = this.count + 1;
    }
  },
  mounted: function() {
    this.count = this.initial_count;
  }
});

Transitions

Vue provides a variety of ways to apply transition effects when items are inserted, updated, or removed from the DOM. This includes tools to:

• automatically apply classes for CSS transitions and animations
• integrate 3rd-party CSS animation libraries, such as Animate.css
• use JavaScript to directly manipulate the DOM during transition hooks
• integrate 3rd-party JavaScript animation libraries, such as Velocity.js

When an element wrapped in a transition component is inserted or removed, this is what happens:

1. Vue will automatically sniff whether the target element has CSS transitions or animations applied. If it does, CSS transition classes will be added/removed at appropriate timings.
2. If the transition component provided JavaScript hooks, these hooks will be called at appropriate timings.
3. If no CSS transitions/animations are detected and no JavaScript hooks are provided, the DOM operations for insertion and/or removal will be executed immediately on next frame.

Routing

Vue itself doesn’t come with routing. But there’s the vue-router package to help you out. It supports mapping nested routes to nested components and offers fine-grained transition control. Creating a Single-page Application with Vue + vue-router is dead simple. With Vue, we are already composing our application with components. When adding vue-router to the mix, all we need to do is map our components to the routes and let vue-router know where to render them.

Supporting libraries

• vue-router
• vuex
• vue-loader
• vueify 
• vue-cli

See also

• Comparison of JavaScript frameworks
• React (JavaScript library)
• AngularJS
• JavaScript Framework
• JavaScript Library