VueScript2 - Simple, Familiar Asynchronous Script Loading

VueScript2 brings back the <script> tag to your SPA (Single Page App)!

This tiny library should take care of all your declarative and imperative asynchronous loading needs. Web designers can rest easy knowing their existing knowledge of web development is still useful!

This version is tailored for the Vue.js framework, but it's easy to port to Riot.js and others.

VueScript2 is primarily for internal use and not for standalone components that are being shared publicly. Those should be "self-contained" and come with all the JS they need.

NOTE: Requires Vue 2.x. Use version 1.2.2 for Vue 1.x.

Features

• Just like <script> except with a 2, but even that can be fixed!
• Keep your app.js bundle small!
• Embrace Web Standards™ everyone knows and loves!
• Easy for web designers to pick up! If you know HTML, you already know how to use it!
• Tiny! Less than 1kb! (min+gzip'd)
• Perfect for use in .ejs templates or .html files!
• No more including every library on every page or complicated "code splitting"!
• Ordered execution based on position in markup!
• Special unload attribute can be used to keep your app's memory usage low!
• Does imperative loading too!

Installation

npm install vue-script2 --save

Then enable the plugin (in your main.js or wherever):

Vue.use(require('vue-script2'))

Or with import:

import Vue from 'vue'
import VS2 from 'vue-script2'

Vue.use(VS2)

Usage

Note: you can write <script> instead of <script2> using script2ify! :smile:

Familiar, declarative, asynchronous loading of scripts

Using vue-script2 with vue-router is simple. Say that only one of your routes displays a "page" that makes use of jQuery. Well, no need to include all of jQuery in your app.js bundle, now you can throw this in:

<script2 src="/path/to/jquery.min.js"></script2>

Boom!

And don't worry, script2 won't re-download scripts if they're already loaded.

Promise-based imperative loading too!

Imperatively load scripts with VueScript2.load:

VueScript2.load('/path/to/jquery.min.js').then(function () {
  $('#msg').text('Hello from VueScript2!')
})

For 99% of use-cases this is totally sufficient and you do not need the overhead of RequireJS or SystemJS or whatever else. That's especially true given that Vue.js is normally used with Browserify or Webpack, which handle complicated dependency management for you.

NOTE: scripts injected using VueScript2.load are always async.

Delayed execution of inlined JavaScript

Want to run some JavaScript only when a specific "page"/route is visited and only after a library has finished loading? Simple!

<script2 src="/path/to/jquery.min.js"></script2>
<script2>
// Ordered execution should ensure that '$' is available here
$(document).ready(function () {
  // this code runs *only* when the route
  // that contains this code is loaded! :D->-<
})
</script2>

Cleanup unused resources with the unload attribute

The unload attribute accepts JS expressions to run when the component is destroyed. This prevents your SPA from accumulating stuff in memory that's not being used:

<script2 src="/path/to/jquery.min.js" unload="jQuery.noConflict(true)"></script2>

Special support for async attribute

Although technically all scripts are inserted with s.async = false (since we're using document.write, see this wonderful article by Jake Archibald for details), setting the async attribute does make a meaningful difference.

By default, the loading of <script2> tags is serialized using promises so that one script loads after another has finished. If you don't care about the loading order, add async to have the script injected into the page immediately.

You can mix and match so that some <script2> tags are loaded immediately while others wait for the ones before them:

<script2 src="jquery.min.js"></script2>
<script2>$('#foo').text('hi!')</script2>
<!-- Load next script immediately, don't wait for jQuery -->
<script2 src="lib.js" async></script2>

Writing <script> instead of <script2> using script2ify

The script2ify browserify transform below will (fairly safely) dynamically replace <script> tags with <script2> tags within .ejs, .html, and even .vue files!

var through = require('through2')
// This will replace <script> with <script2> in .html, .vue and .ejs files
// EXCEPT:
// - within <!-- comments -->
// - top-level <script> tags within .vue files
// Additional exclusion per: http://www.rexegg.com/regex-best-trick.html
// Excluding <pre> tags did not seem to work, however.
function script2ify (file) {
  return !/\.(vue|html|ejs)$/.test(file) // edit to support other file types
  ? through()
  : through(function (buf, encoding, cb) {
    // avoid replacing top-level <script> tags in .vue files
    var regex = /\.vue$/.test(file)
    ? /<!--.*?-->|^<script>|^<\/script>|(?:<(\/)?script([ >]))/gm
    : /<!--.*?-->|(?:<(\/)?script([ >]))/gm
    var replacement = (m, p1, p2) => p2 ? `<${p1 || ''}script2${p2}` : m
    cb(null, buf.toString('utf8').replace(regex, replacement))
  })
}

History

See CHANGELOG.md

License

MIT