A Browserify transform for bundling, rebasing, inlining, and minifying CSS files.
JavaScript
Latest commit 7f6b851 Jan 26, 2017 @cheton Merge branch 'dev'

README.md

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NPM

A Browserify transform for bundling, rebasing, inlining, and minifying CSS files. It's useful for CSS modularization where styles are scoped to their related bundles.

Getting Started

If you're new to browserify, check out the browserify handbook and the resources on browserify.org.

Installation

npm install --save-dev browserify-css

Usage

app.css:

@import url("modules/foo/index.css");
@import url("modules/bar/index.css");
body {
    background-color: #fff;
}

app.js:

var css = require('./app.css');
console.log(css);

You can compile your app by passing -t browserify-css to browserify:

$ browserify -t browserify-css app.js > bundle.js

Each require('./path/to/file.css') call will concatenate CSS files with @import statements, rebasing urls, inlining @import, and minifying CSS. It will add a style tag with an optional data-href attribute to the head section of the document during runtime:

<html>
<head>
    <style type="text/css" data-href="app.css">...</style>
</head>
</html>

Configuration

You can set configuration to your package.json file:

{
    "browserify-css": {
        "autoInject": true,
        "minify": true,
        "rootDir": "."
    }
}

or use an external configuration file like below:

{
    "browserify-css": "./config/browserify-css.js"
}

config/browserify-css.js:

module.exports = {
    "autoInject": true,
    "minify": true,
    "rootDir": "."
};

Furthermore, browserify-css transform can obtain options from the command-line with subarg syntax:

$ browserify -t [ browserify-css --autoInject=true ] app.js

or from the api:

b.transform('browserify-css', { autoInject: true })

Options

autoInject

Type: Boolean Default: true

If true, each require('path/to/file.css') call will add a style tag to the head section of the document.

autoInjectOptions

Type: Object Default:

{
    "verbose": true,
    "insertAt": "bottom" // or "top"
}

verbose

If verbose is set to true, the path to CSS will be specified in the data-href attribute inside the style tag

insertAt

By default, browserify-css transform appends <style> elements to the end of the <head> tag of the page. This will cause CSS created by browserify-css transform to take priority over CSS already present in the document head. To insert style elements at the beginning of the head, set the insertAt parameter to 'top'.

inlineImages

Type: Boolean or Object Default: false

If true, each required css file will have image url() replaced with data urls. For example from:

  background-image: url("background.png");

to:

  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAVQAAAHgCAYAAAD6yZXWAAAABmJLR0QA");

options

Using the object syntax you can specify additional options for the inlineImages option:

{
    "options": { // maximum size (in bytes) of image file that will be inlined into css file
        "limit": 0 // 0 means no limit - inline all images
    }
}

If a limit is set, then only files that are smaller than the number of bytes given will be inlined into the css file.

minify

Type: Boolean Default: false

minifyOptions

Type: Object Default: {}

Check out a list of CSS minify options at CleanCSS.

onFlush

Type: Function

The onFlush option accepts a function which takes two arguments: (options, done).

// @param {object} options The options object
// @param {string} options.filename The filename
// @param {string} options.data The CSS file content
// @param {string} options.rootDir The root directory
// @param {string} options.relativePath The relative path
// @param {string} options.href The href attribute
// @param {function} done The done callback
onFlush: function(options, done) {
    // Method 1:
    // This will keep original module.exports unchanged
    done();

    // Method 2:
    // Pass a null value to the done callback if you do not want to embed CSS into a JavaScript bundle
    done(null);

    // Method 3:
    // Pass a text string to the done callback to customize module.exports
    done('module.exports = ' + JSON.stringify(options.data) + ';');
}

You can use the onFlush option to output each CSS to a separate file, or append multiple CSS into one file. For example:

var browserify = require('browserify');
var fs = require('fs');

fs.unlinkSync('dist/assets/app.css');

browserify(options)
    .add('src/index.js')
    .transform(require('browserify-css'), {
        rootDir: 'src',
        onFlush: function(options, done) {
            fs.appendFileSync('dist/assets/app.css', options.data);

            // Do not embed CSS into a JavaScript bundle
            done(null);
        }
    })
    .bundle();

processRelativeUrl

Type: Function

The processRelativeUrl option accepts a function which takes one argument (the relative url) and returns the original relativeUrl string or the converted result. For example:

var browserify = require('browserify');

browserify(options)
    .add('src/index.js')
    .transform(require('browserify-css'), {
        rootDir: 'src',
        processRelativeUrl: function(relativeUrl) {
            return relativeUrl;
        }
    })
    .bundle();

You can embed the image data directly into the CSS file with data URI, like so:

var _ = require('lodash');
var path = require('path');
var browserify = require('browserify');

browserify(options)
    .add('src/index.js')
    .transform(require('browserify-css'), {
        rootDir: 'src',
        processRelativeUrl: function(relativeUrl) {
            if (_.contains(['.jpg','.png','.gif'], path.extname(relativeUrl))) {
                // Embed image data with data URI
                var DataUri = require('datauri');
                var dUri = new DataUri(relativeUrl);
                return dUri.content;
            }
            return relativeUrl;
        }
    })
    .bundle();

You may also want to check out the FAQ for advanced usage.

rebaseUrls

Type: Boolean Default: true

If true, relative paths will be rebased in css files; if false, paths will be unchanged.

rootDir

Type: String Default: ./

An absolute path to resolve relative paths against the project's base directory.

FAQ

1. How do I include CSS files located inside the node_modules folder?

You can choose one of the following methods to include CSS files located inside the node_modules folder:

  1. The easiest way to do this is using the @import rule. For example:

    app.js:

    require('./app.css');

    app.css:

    /* Use CSS from your node_modules folder */
    @import "node_modules/foo/foo.css";
    
    /* Or your own relative files */
    @import "styles/common.css";
  2. Use the global transform option (i.e. --global-transform or -g) on the command line to transform all files in a node_modules directory:

    $ browserify -g browserify-css app.js > bundle.js 

    or use the API directly:

    var browserify = require('browserify');
    var b = browserify('./app.js');
    b.transform('browserify-css', {global: true});
    b.bundle().pipe(process.stdout);

    See browserify transform options for details.

    Then you will be able to require CSS files from within node_modules. For example:

    require('bootstrap/dist/bootstrap.css');
  3. Put browserify transform option into a submodule's package.json file inside the node_modules directory on a per-module basis like so:

    node_modules/foo/package.json:

    {
      "browserify": {
        "transform": ["browserify-css"]
      }
    }

    Then, run browserify transform on the command line:

    $ browserify -t browserify-css app.js > bundle.js 

2. How do I load font and image files from node_modules?

Assume that you have the following directory structure:

package.json
dist/
src/
    index.js
    index.css
node_modules/
    bootstrap/
        dist/
            css/
                bootstrap.css

The index.css uses @import to import external style sheets:

@import url("../node_modules/bootstrap/dist/css/bootstrap.css");

All output files, including the generated bundle.js, are created under the dist directory:

dist/
    bundle.js
    vendor/
        bootstrap/
            dist/
                css/
                    bootstrap.css

Suppose that the dist directory is your web root, you might want to copy external font and images files from ../node_modules/ to dist/vendor/.

For example, the @font-face rules in node_modules/bootstrap/dist/css/bootstrap.css:

@font-face {
    font-family: 'Glyphicons Halflings';
    src: url('../fonts/glyphicons-halflings-regular.eot');
    src: url('../fonts/glyphicons-halflings-regular.eot?#iefix') format('embedded-opentype'),
         url('../fonts/glyphicons-halflings-regular.woff2') format('woff2'),
         url('../fonts/glyphicons-halflings-regular.woff') format('woff'),
         url('../fonts/glyphicons-halflings-regular.ttf') format('truetype'),
         url('../fonts/glyphicons-halflings-regular.svg#glyphicons_halflingsregular') format('svg');
}

The example below illustrates the use of the processRelativeUrl option:

var gulp = require('gulp');
var gutil = require('gulp-util');
var path = require('path');
var browserify = require('browserify');
var sourceStream = require('vinyl-source-stream');
var fse = require('fs-extra');

var bundleStream = browserify()
    .add('src/index.js')
    .transform(require('browserify-css'), {
        rootDir: 'src',
        processRelativeUrl: function(relativeUrl) {
            var stripQueryStringAndHashFromPath = function(url) {
                return url.split('?')[0].split('#')[0];
            };
            var rootDir = path.resolve(process.cwd(), 'src');
            var relativePath = stripQueryStringAndHashFromPath(relativeUrl);
            var queryStringAndHash = relativeUrl.substring(relativePath.length);

            //
            // Copying files from '../node_modules/bootstrap/' to 'dist/vendor/bootstrap/'
            //
            var prefix = '../node_modules/';
            if (_.startsWith(relativePath, prefix)) {
                var vendorPath = 'vendor/' + relativePath.substring(prefix.length);
                var source = path.join(rootDir, relativePath);
                var target = path.join(rootDir, vendorPath);

                gutil.log('Copying file from ' + JSON.stringify(source) + ' to ' + JSON.stringify(target));
                fse.copySync(source, target);

                // Returns a new path string with original query string and hash fragments
                return vendorPath + queryStringAndHash;
            }

            return relativeUrl;
        }
    })
    .bundle();

bundleStream
    .pipe(sourceStream(bundleFile))
    .pipe(gulp.dest(browserifyConfig.dest));

Acknowledgements

Test Images:

License

Copyright (c) 2014-2017 Cheton Wu

Licensed under the MIT License.