PostHTML Minifier

Modular HTML minifier, built on top of the PostHTML. Inspired by cssnano.

Usage

Gulp

npm install --save-dev gulp-htmlnano

var gulp = require('gulp');
var htmlnano = require('gulp-htmlnano');
var options = {
    removeComments: false
};

gulp.task('default', function() {
    return gulp
        .src('./index.html')
        .pipe(htmlnano(options))
        .pipe(gulp.dest('./build'));
});

Javascript

var htmlnano = require('htmlnano');
var options = {
    removeEmptyAttributes: false, // Disable the module "removeEmptyAttributes"
    collapseWhitespace: 'conservative' // Pass options to the module "collapseWhitespace"
};

htmlnano.process(html, options).then(function (result) {
    // result.html is minified
});

PostHTML

Just add htmlnano as the last plugin:

var posthtml = require('posthtml');
var options = {
    removeComments: false, // Disable the module "removeComments"
    collapseWhitespace: 'conservative' // Pass options to the module "collapseWhitespace"
};

posthtml([
    /* other PostHTML plugins */

    require('htmlnano')(options)
]).process(html).then(function (result) {
    // result.html is minified
});

Modules

By default all modules are enabled. You can disable some of them by passing module name with false in the plugin options (like in the usage example above).

collapseWhitespace

Collapses redundant white spaces (including new lines). It doesn’t affect white spaces in the elements <style>, <textarea>, <script>, and <pre>.

Options:

• all — collapses all redundant white spaces (default)
• conservative — collapses all redundant white spaces to 1 space

Source:

<div>
    hello  world!
    <style>div  { color: red; }  </style>
</div>

Minified (with all):

<div>hello world!<style>div  { color: red; }  </style></div>

Minified (with conservative):

<div> hello world! <style>div  { color: red; }  </style> </div>

This module can have side effects. <i>hello</i> <i>world</i> after minification will be rendered as helloworld. To prevent that use conservative option.

removeComments

Options:

• safe – removes all HTML comments except <!--noindex--><!--/noindex--> (default)
• all — removes all HTML comments

Source:

<div><!-- test --></div>

Minified:

<div></div>

removeEmptyAttributes

Removes empty safe-to-remove attributes.

Source:

<img src="foo.jpg" alt="" style="">

Minified:

<img src="foo.jpg" alt="">

minifyCss

Minifies CSS with cssnano inside <style> tags and style attributes.

Options: See the documentation of cssnano. For example you can keep outdated vendor prefixes:

htmlnano.process(html, {
    minifyCss: {
        autoprefixer: false
    }
});

Source:

<div>
    <style>
        h1 {
            margin: 10px 10px 10px 10px;
            color: #ff0000;
        }
    </style>
</div>

Minified:

<div>
    <style>h1{margin:10px;color:red}</style>
</div>

minifyJs

Minifies JS with UglifyJS2 inside <script> tags.

Options: See the API documentation of UglifyJS2

Source:

<div>
    <script>
        /* comment */
        var foo = function () {

        };
    </script>
</div>

Minified:

<div>
    <script>var foob=function(){};</script>
</div>

custom

It's also possible to pass custom modules in the minifier.

As a function:

var options = {
    custom: function (tree, options) {
        // Some minification
        return tree;
    }
};

Or as a list of functions:

var options = {
    custom: [
        function (tree, options) {
            // Some minification
            return tree;
        },

        function (tree, options) {
            // Some other minification
            return tree;
        }
    ]
};

options is an object with all options that were passed to the plugin.

Contribute

Since the minifier is modular, it's very easy to add new modules:

1. Create a ES6-file inside lib/modules/ with a function that does some minification. For example you can check lib/modules/example.es6.

2. Add the module in the modules array. The modules are applied from top to bottom. So you can choose the order for your module.

3. Create a JS-file inside test/modules/ with some unit-tests.

4. Describe your module in the section "Modules".

5. Send me a pull request.

Other types of contribution (bug fixes, documentation improves, etc) are also welcome! Would like to contribute, but don't have any ideas what to do? Check out our issues.