script-fallback-from-urls

Create HTML tags to load a JavaScript file safely

var html = scriptFallbackFromUrls('window.angular', [
  '//ajax.googleapis.com/ajax/libs/angularjs/1.2.21/angular.min.js',
  'path/to/local/angular.min.js'
], {min: false});

console.log(html);

yields:

<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.21/angular.min.js"></script>
<script>window.angular||document.write('path/to/local/angular.min.js');</script>

Installation

Package managers

npm

npm i --save script-fallback-from-urls

Bower

bower i --save script-fallback-from-urls

Duo

var scriptFallbackFromUrls = require('shinnn/script-fallback-from-urls');

API

scriptFallbackFromUrls(variable, urls [, option])

variable: String (global variable name the library should creates)
urls: array of String (URL of CDNs and local copy)
option: Object
Return: String

It returns an HTML text of <script> tags to load the script with single or multiple fallbacks.

Generated HTML tries to load the script from the URLs in order. If the first URL doesn't provide the global variable you specified — in most case, when the script isn't loaded successfully, it tries to load from the second URL, and so forth.

It is highly recommended that the last URL points at a local copy on your server because it is used as a last resort.

scriptFallbackFromUrls('window.THREE', [
  '//ajax.googleapis.com/ajax/libs/threejs/r67/three.min.js',
  '//cdnjs.cloudflare.com/ajax/libs/three.js/r68/three.min.js',
  'path/to/local/three.min.js'
]);
//=> <script src="//ajax.googleapis.com/ajax/libs/threejs/r67/three.min.js"></script><script>window.THREE||document.write(\'//cdnjs.cloudflare.com/ajax/libs/three.js/r68/three.min.js\')</script><script>window.THREE||document.write(\'path/to/local/three.min.js\')</script>

option.min

Type: Boolean
Default: true

Adds newlines and semicolons by setting this option false.

scriptFallbackFromUrls('window.THREE', [
  '//ajax.googleapis.com/ajax/libs/threejs/r67/three.min.js',
  '//cdnjs.cloudflare.com/ajax/libs/three.js/r68/three.min.js',
  'path/to/local/three.min.js'
], {min: false});

/* =>
<script src="//ajax.googleapis.com/ajax/libs/threejs/r67/three.min.js"></script>
<script>window.THREE||document.write('//cdnjs.cloudflare.com/ajax/libs/three.js/r68/three.min.js');</script>
<script>window.THREE||document.write('path/to/local/three.min.js');</script>
*/

CLI

You can use this module as a CLI tool by installing it globally.

npm install -g inline-source-map-comment

Usage

script-fallback-from-urls v1.0.0
Create script tags to load a JavaScript file with single or multiple fallbacks

Usage: script-fallback-from-urls <url1> <url2> [<url3> ...] --variable <variable>

--variable, --var, -V  Specify a required global variable

Options:
--no-min,              Do not minify output
--help,            -h  Print usage information
--version,         -v  Print version

Example

$ script-fallback-from-urls http://d3js.org/d3.v3.min.js path/to/local/d3.v3.min.js --variable d3
> <script src="http://d3js.org/d3.v3.min.js"></script><script>d3||document.write('path/to/local/d3.v3.min.js')</script>

License

Copyright (c) 2014 - 2015 Shinnosuke Watanabe

Licensed under the MIT License.