minimize/README.md

Minimize HTML

# HTML minifier

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Minimize is a HTML minifier based on the node-htmlparser. This depedency will
ensure output is solid and correct. Minimize is focussed on HTML5 and will not
support older HTML drafts. It is not worth the effort and the web should move
forward. Currently, HTML minifier is only usuable server side. Client side
minification will be added in a future release.



**Minimize does not parse inline PHP or raw template files. Templates are not valid
HTML and this is outside the scope of the minimize. The _output_ of the
templaters should be parsed and minified.**

## Features

- fast and stable HTML minification (no inline PHP or templates)
- highly configurable
- CLI interface usable with stdin and files
- can distinguish conditional IE comments and/or SSI
- build on the foundations of [htmlparser2][fb55]
- pluggable interface that allows to hook into each element

## Usage

To get the minified content make sure to provide a callback. Optional an options
object can be provided. All options are listed below and `false` per default.

```js
var Minimize = require('minimize')
  , content = new Minimize().parse(content);

console.log(content);
```

#### Asynchronous usage

Simply pass a callback as second argument. This is relevant is plugins perform
asynchronous operations.

```js
var Minimize = require('minimize')
  , minimize = new Minimize();

minimize.parse(content, function (error, data) {
  console.log(data);
});
```

#### Gulp plugin

- [gulp-minimize](https://github.com/foru17/gulp-minimize): Gulp plugin based on minimize.

#### Options

List of available options. Note that all options are set to `false` by default and
need to be explicitly enabled by providing `true`. For example `empty: true`.

- [empty](#empty)
- [cdata](#cdata)
- [comments](#comments)
- [ssi](#server-side-includes-ssi)
- [conditionals](#conditionals)
- [spare](#spare)
- [quotes](#quotes)
- [loose](#loose)
- [dom](#dom)
  - xmlMode
  - lowerCaseAttributeNames
  - lowerCaseTags

#### Custom parser

Supplying a custom instance to do the HTML parsing is possible. I.e. this can
be useful if the HTML contains SVG or if you need to specific options to the parser.

```js
var Minimize = require('minimize')
  , html = require('htmlparser2')
  , minimize = new Minimize(
      new html.Parser(
        new html.FeedHandler(minimize.emits('read')),
        { /* options */ }
      )
    );

minimize.parse(content, function (error, data) {
  console.log(data);
});
```

## Options

###### Empty

Empty attributes can usually be removed, by default all are removed, excluded
HTML5 _data-*_ and microdata attributes. To retain empty elements regardless
value, do:

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ empty: true });

minimize.parse(
  '<h1 id=""></h1>',
  function (error, data) {
    // data output: <h1 id=""></h1>
  }
);
```

###### CDATA

CDATA is only required for HTML to parse as valid XML. For normal webpages this
is rarely the case, thus CDATA around javascript can be omitted. By default
CDATA is removed, if you would like to keep it, pass true:

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ cdata: true });

minimize.parse(
  '<script type="text/javascript">\n//<![CDATA[\n...code...\n//]]>\n</script>',
  function (error, data) {
    // data output: <script type=text/javascript>//<![CDATA[\n...code...\n//]]></script>
  }
);
```

###### Comments

Comments inside HTML are usually beneficial while developing. Hiding your
comments in production is sane, safe and will reduce data transfer. If you
ensist on keeping them, fo1r instance to show a nice easter egg, set the option
to true. Keeping comments will also retain any Server Side Includes or
conditional IE statements.

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ comments: true });

minimize.parse(
  '<!-- some HTML comment -->\n     <div class="slide nodejs">',
  function (error, data) {
    // data output: <!-- some HTML comment --><div class="slide nodejs">
  }
);
```

###### Server Side Includes (SSI)

Server side includes are special set of commands that are support by several
web servers. The markup is very similar to regular HTML comments. Minimize can
be configured to retain SSI comments.

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ ssi: true });

minimize.parse(
  '<!--#include virtual="../quote.txt" -->\n     <div class="slide nodejs">',
  function (error, data) {
    // data output: <!--#include virtual="../quote.txt" --><div class="slide nodejs">
  }
);
```

###### Conditionals

Conditional comments only work in IE, and are thus excellently suited to give
special instructions meant only for IE. Minimize can be configured to retain
these comments. But since the comments are only working until IE9 (inclusive)
the default is to remove the conditionals.

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ conditionals: true });

minimize.parse(
  "<!--[if ie6]>Cover microsofts' ass<![endif]-->\n<br>",
  function (error, data) {
    // data output: <!--[if ie6]>Cover microsofts' ass<![endif]-->\n<br>
  }
);
```

###### Spare

Spare attributes are of type boolean of which the value can be omitted in HTML5.
To keep attributes intact for support of older browsers, supply:

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ spare: true });

minimize.parse(
  '<input type="text" disabled="disabled"></h1>',
  function (error, data) {
    // data output: <input type=text disabled=disabled></h1>
  }
);
```

###### Quotes

Quotes are always added around attributes that have spaces or an equal sign in
their value. But if you require quotes around all attributes, simply pass
quotes:true, like below.

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ quotes: true });

minimize.parse(
  '<p class="paragraph" id="title">\n    Some content\n  </p>',
  function (error, data) {
    // data output: <p class="paragraph" id="title">Some content</p>
  }
);
```

###### Loose

Minimize will only keep whitespaces in structural elements and remove all other
redundant whitespaces. This option is useful if you need whitespace to keep the
flow between text and input elements. Downside: whitespaces or newlines after
block level elements will also have one trailing whitespace.

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ loose: true });

minimize.parse(
  '<h1>title</h1>  <p class="paragraph" id="title">\n  content\n  </p>    ',
  function (error, data) {
    // data output: <h1>title</h1> <p class="paragraph" id="title"> content </p> '
  }
);
```

###### dom

Minimize use !(htmlparser2)[https://github.com/fb55/htmlparser2] to parse the dom. The `dom` option permit to customize htmlparser2.

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ dom: { lowerCaseAttributeNames: false }});

minimize.parse(
  '<a *ngIf="bool">link</a>',
  function (error, data) {
    // data output: <a *ngIf=bool>link</a> '
  }
);
```

## Plugins

Register a set of plugins that will be ran on each iterated element. Plugins
are ran in order, errors will stop the iteration and invoke the completion
callback.

```js
var Minimize = require('minimize')
  , minimize = new Minimize({ plugins: [{
      id: 'remove',
      element: function element(node, next) {         // callback is optional
        if (node.type === 'text') delete node.data;
        next();
      }
    }]});

minimize.parse(
  '<h1>title</h1>',
  function (error, data) {
    // data output: <h1></h1>
  }
);
```

**Note:** plugins have no control over the flow of minimize. The DOM
structure that is parsed by [htmlparser2][fb55] is asynchronously reduced.
Each element is handed of to the plugin `element` method. Thus, plugins
have full control over properties of each `node` as objects always have
reference in javascript.

#### Available plugins

- [uglifyjs](https://www.npmjs.com/package/minimize-plugin-uglifyjs): minify script content
- [handlebars](https://www.npmjs.com/package/minimize-handlebars-attribs): allow handlebar template tags


## Tests

Tests can be easily run by using either of the following commands. Travis.ci is
used for continous integration.

```bash
make test
make test-watch
npm test
```

## Benchmarks


## Credits
Minimize is influenced by the [HTML minifier][kangax] of kangax. This module
parses the DOM as string as opposes to an object. However, retaining flow is more
diffucult if the DOM is parsed sequentially. Minimize is not client-side ready.
Kangax minifier also provides some additional options like linting. Minimize
will retain strictly to the business of minifying. Minimize is already used in
production by [Nodejitsu][nodejitsu].

[node-htmlparser][fb55] of fb55 is used to create an object representation
of the DOM.

[kangax]: https://github.com/kangax/html-minifier/
[fb55]: https://github.com/fb55/htmlparser2
[nodejitsu]: http://www.nodejitsu.com/