reduce-web-component

Features

• Automatically pack styles together when one component requires another (in scripts).
• Use browserify and depsify to pack scripts and styles into common shared bundles.
• Use watchify2 to watch file changes, addition and deletion.
• Use postcss to preprocess styles by default.

Example

Suppose we put pages under the directory /path/to/src/page, and other components under /path/to/src/node_modules.

A page or component may have a style entry as well as a script entry. For simplicity, entries are named as index.[js|css] if present.

There are two pages (hello and hi), as well as two components (world, earth).

The hello page will present the world component (both scripts and styles needed). We can do this by adding require('world') in hello/index.js, and @import "world"; in hello/index.css. However, if world is no longer needed, we have to remove both require('world') and @import "world", which is really cumbersome.

So, we decide that if the script entry is required, the corresponding style entry should also be @imported. In such cases, we say the component is required. This is achieved by adding style dependencies according to script dependencies.

Eventually, we want scripts required by all pages to be packed into /path/to/build/bundle.js, and styles into /path/to/build/bundle.css.

We can use this package to do that.

Input

The hello page

• Script entry (page/hello/index.js)

module.exports = 'hello, ' + require('world')

• Style entry (page/hello/index.css)

.hello {}

The hi page

• Script entry (page/hi/index.js)

module.exports = 'hi, ' + require('earth')

• Style entry (null)

The world component

• Script entry (node_modules/world/index.js)

module.exports = 'world'

• Style entry (node_modules/world/index.css)

.world {
  color: red;
}

The earth component

• Script entry (node_modules/earth/index.js)

module.exports = 'earth'

• Style entry (node_modules/earth/index.css)

.earth {
  color: blue;
}

The original dependency graph looks like:

The dependency graph we want for bundling should look like:

NOTE As hi requires earth and earth is shipped with styles, hi will need styles at last. So a virtual hi/index.css is created (but not written into disk).

Output

We run the following script to bundle js and css:

'use strict'

const path = require('path')
const reduce = require('reduce-web-component')

const options = {
  getStyle: function (jsFile) {
    return path.dirname(jsFile) + '/index.css'
  },

  reduce: {
    basedir: path.resolve(__dirname, 'src'),
  },

  on: {
    log: console.log.bind(console),
    error: function (err) {
      console.error(err.stack)
    },
    'reduce.end': function (bytes, duration) {
      console.log(
        '[%s done] %d bytes written (%d seconds)',
        this._type, bytes, (duration / 1000).toFixed(2)
      )
    },
  },

  js: {
    entries: 'page/**/index.js',
    bundleOptions: 'bundle.js',
    dest: 'build',
  },

  css: {
    // No need to specify entries,
    // because we have done that implicitly by setting getStyle.
    // entries: 'page/**/index.css',
    bundleOptions: 'bundle.css',
    dest: 'build',
  },
}

reduce.bundle(options).then(() => console.log('DONE'))

Besides hello/index.css and world/index.css, earth/index.css will also be included in bundle.css.

Usage

const reduce = require('reduce-web-component')

// pack
reduce.bundle(options).then(() => {})

// watch mode
reduce.watch(options).on('done', () => {})

To work with gulp:

const gulp = require('gulp')
const reduce = require('reduce-web-component')

gulp.task('build', () => {
  return reduce.bundle(options)
})
gulp.task('watch', function (cb) {
  reduce.watch(options)
    .on('close', cb)
    .on('done', () => console.log('-'.repeat(40)))
})

Common shared bundles

Check the configure file.

Browserify

Scripts are bundled with browserify. So, plugins and transforms can be applied during the build process.

Check browserify-handbook for more information.

PostCss

Styles are preprocessed with postcss. Check reduce-css-postcss to see the default processors.

depsify is used to bundle styles, so that styles can be packed into common shared multiple bundles.

options

Options for both JS and CSS bundling are configurable.

Check reduce-js and reduce-css for the following options:

• entries. Type: String, Array. Optional Globs to locate entries.
• reduce. Type: Object. Options passed to browserify or depsify.
• bundleOptions. Type: Object. Options passed to common-bundle.
• dest. Type: String, Array. Options passed to [b.dest].
• watch. Type: Object. Options passed to watchify2.

Other options:

• on. Type: Object. Listeners to be added to the bundler instance.
• plugin. Plugins to process the vinyl stream. They are just like gulp plugins.

Example:

{
  js: { 
    entries: 'page/**/index.js',
    reduce: { basedir: '/path/to/src' },
    bundleOptions: {
      groups: 'page/**/index.js',
      common: 'common.js',
    },
    watch: {
      ignoreWatch: ['**/node_modules/**'],
      entryGlob: 'page/**/index.js',
    },
    on: { 
      'common.map': o => {},
      error: console.log,
    }
  },
  css: {
    entries: 'page/**/index.css',
    reduce: { basedir: '/path/to/src' },
    bundleOptions: { groups: 'page/**/index.css', common: 'common.css' },
    watch: {
      ignoreWatch: ['**/node_modules/**'],
      entryGlob: 'page/**/index.css',
    },
    on: { 
      error: console.log,
    }
  },
}

Meanwhile, we have:

• getStyle: bind JS and CSS together so that when js is required, the corresponding css will also be imported implicitly by the dependant's css.

{ 
  getStyle: jsFile => { 
    return path.dirname(jsFile) + '/index.css'
  },
  js: {},
  css: {},
}

Suppose there are /path/to/component/x/index.js and /path/to/component/y/index.js, and their binding CSS are /path/to/component/x/index.css and /path/to/component/y/index.css respectively.

If we require('../y') in x/index.js, then CSS will be bundled as if there is @external "../y"; in x/index.css.

Common options for both options.js and options.css could also be specified as properties of options:

{
  // common options
  reduce: { basedir: '/path/to/src' },
  on: { 
    error: console.log,
  },

  js: { 
    entries: 'page/**/index.js',
    bundleOptions: {
      groups: 'page/**/index.js',
      common: 'common.js',
    },
    watch: {
      ignoreWatch: ['**/node_modules/**'],
      entryGlob: 'page/**/index.js',
    },
    on: { 
      'common.map': o => {},
    }
  },
  css: {
    entries: 'page/**/index.css',
    bundleOptions: { groups: 'page/**/index.css', common: 'common.css' },
    watch: {
      ignoreWatch: ['**/node_modules/**'],
      entryGlob: 'page/**/index.css',
    },
  },
}

Environment-specific options are possible:

{
  reduce: { basedir: '/path/to/src' },
  on: { 
    error: console.log,
  },

  js: { 
    entries: 'page/**/index.js',
    bundleOptions: {
      groups: 'page/**/index.js',
      common: 'common.js',
    },
    watch: {
      ignoreWatch: ['**/node_modules/**'],
      entryGlob: 'page/**/index.js',
    },
    on: { 
      'common.map': o => {},
    }
  },
  css: {
    entries: 'page/**/index.css',
    bundleOptions: { groups: 'page/**/index.css', common: 'common.css' },
    watch: {
      ignoreWatch: ['**/node_modules/**'],
      entryGlob: 'page/**/index.css',
    },
  },
  env: { 
    development: { 
      js: { 
        reduce: { 
          plugin: ['index-hashify', 'browserify-hmr']
        },
      }
    },
    production: { 
      js: { 
        plugin: 'gulp-uglify'
      },
      css: { 
        plugin: 'gulp-uglifycss'
      }
    },
  }
}

Related

• reduce-js
• reduce-css