node package manager

useref

Parse build blocks in HTML files to replace references

useref Build Status Coverage Status

NPM

Parse build blocks in HTML files to replace references

Extracted from the grunt plugin grunt-useref.

Installation

npm install useref

Usage

var useref = require('useref');
var result = useref(inputHtml);
// result = [ replacedHtml, { type: { path: { 'assets': [ replacedFiles] }}} ] 

Blocks are expressed as:

<!-- build:<type>(alternate search path) <path> <parameters> -->
... HTML Markup, list of script / link tags.
<!-- endbuild -->
  • type: either js, css or remove
  • alternate search path: (optional) By default the input files are relative to the treated file. Alternate search path allows one to change that
  • path: the file path of the optimized file, the target output
  • parameters: extra parameters that should be added to the tag

An example of this in completed form can be seen below:

<html>
<head>
  <!-- build:css css/combined.css -->
  <link href="css/one.css" rel="stylesheet">
  <link href="css/two.css" rel="stylesheet">
  <!-- endbuild -->
</head>
<body>
  <!-- build:js scripts/combined.js -->
  <script type="text/javascript" src="scripts/one.js"></script> 
  <script type="text/javascript" src="scripts/two.js"></script> 
  <!-- endbuild -->
 
  <!-- build:js scripts/async.js async data-foo="bar" -->
  <script type="text/javascript" src="scripts/three.js"></script> 
  <script type="text/javascript" src="scripts/four.js"></script> 
  <!-- endbuild -->
</body>
</html>

The module would be used with the above sample HTML as follows:

var result = useref(sampleHtml);
 
// [ 
//   resultHtml, 
//   { 
//     css: { 
//       'css/combined.css': { 
//         'assets': [ 'css/one.css', 'css/two.css' ] 
//       } 
//     }, 
//     js: { 
//       'scripts/combined.js': { 
//         'assets': [ 'scripts/one.js', 'scripts/two.js' ] 
//       }, 
//       'scripts/async.js': { 
//          'assets': [ 'scripts/three.js', 'scripts/four.js' ] 
//        } 
//     } 
//   } 
// ] 

The resulting HTML would be:

<html>
<head>
  <link rel="stylesheet" href="css/combined.css"/>
</head>
<body>
  <script src="scripts/combined.js"></script> 
  <script src="scripts/async.js" async data-foo="bar" ></script> 
</body>
</html>

IE Conditional Comments

Internet Explorer Conditional Comments are preserved. The code below:

<!-- build:js scripts/combined.js   -->
<!--[if lt IE 9]>
<script type="text/javascript" src="scripts/this.js"></script>
<script type="text/javascript" src="scripts/that.js"></script>
<![endif]-->
<!-- endbuild -->

Results in:

<!--[if lt IE 9]>
<script src="scripts/combined.js"></script>
<![endif]-->

Custom blocks

Sometimes you need a bit more. If you would like to do custom processing, this is possible with a custom block, as demonstrated below.

<!-- build:import components -->
<link rel="import" href="/bower_components/some/path"></link>
<!-- endbuild -->

With

var useref = require('useref');
var result = useref(inputHtml, {
  // each property corresponds to any blocks with the same name, e.g. "build:import" 
  import: function (content, target, options, alternateSearchPath) {
    // do something with `content` and return the desired HTML to replace the block content 
    return content.replace('bower_components', target);
  }
});

Becomes

<link rel="import" href="/components/some/path"></link>

The handler function gets the following arguments:

  • content (String): The content of the custom use block
  • target (String): The "path" value of the use block definition
  • options (String): The extra attributes from the use block definition, the developer can parse as JSON or do whatever they want with it
  • alternateSearchPath (String): The alternate search path that can be used to maintain a coherent interface with standard handlers

Include a handler for each custom block type.

Options

options.noconcat

Type: Boolean
Default: false

Strips out build comments but leaves the rest of the block intact without replacing any tags.

<!-- build:js scripts/combined.js   -->
<script type="text/javascript" src="scripts/this.js"></script>
<script type="text/javascript" src="scripts/that.js"></script>
<!-- endbuild -->

Results in:

<script type="text/javascript" src="scripts/this.js"></script>
<script type="text/javascript" src="scripts/that.js"></script>

Contributing

See the CONTRIBUTING Guidelines

License

MIT © Jonathan Kemp