bemify

Bemify is a set of Sass mixins to help you write well-structured, readable, maintainable, component-based modular SCSS source using a BEM-style syntax.

Bemify site & documentation: http://franzheidl.github.io/bemify/

Bemify supports libsass since libsass 3.2.4.

Install

Bemify can be installed as a Ruby Gem, via Bower, NPM, or manually. As a NPM module, bemify supports eyeglass. Bemify is also on Sache.in.

Bower

To install via bower run:

$ bower install bemify --save-dev

Ruby Gem

When installed as a Ruby Gem, Bemify will be installed as a Compass extension if Compass is installed on your system.

$ gem install bemify

npm

To install via npm run:

$npm install bemify --save-dev

Manual Install

Include sass/_bemify.scssin the appropriate location in your project.

Usage

First, import bemify:

@import 'bemify';

Once imported, the bemify mixins can now be used to write BEM-style SCSS, making your source cleaner and easier to read and change.

@include block('my-element') {
    …

    @include element('child') {
      …
    }

    @include modifier('small') {
      …
    }

    @include modifier('large') {
      …
    }

    @include state('active') {
      …
    }

}

The output will be full, non-nested BEM-style class selectors:

.my-element {
  …
}

.my-element__child {
  …
}

.my-element--large {
  …
}

.my-element.is-active {
  …
}

By default, bemify will output combined .block.state / .block__element.state selectors. Bemify can also be configured to output full .block--state / .block__element--state selectors. For details, see Configuration below.

The mixins can be nested to create modifiers for subcomponents:

@include block('my-element') {

    @include element('child') {
        …
        @include modifier('bad') {
            …
            @include state('happy') {
                …
            }
        }
    }

    @include modifier('large') {
        …
    }

    @include state('active') {
        …
    }

}

This will result in:

.my-element {
    …
}

.my-element__child {
    …
}

.my-element__child--bad {
    …
}

.my-element__child--bad.is-happy {
    …
}

.my-element--large {
    …
}

.my-element.is-active {

}

Scoping

Bemify can can of course also be used inside any scope:

.scope {

	@include block('nav') {

		// etc.

	}

}

Configuration Options

bemify uses some configuration variables where to adjust the block-element and the state separator, as well as the state prefix. To overwrite bemify's config with your own configuration file, just import your variables before using one of the mixins.

@import "your-variables";
@import "bemify";

@include block('my-block') {
    …
}

Configurable options and their defaults are:

• $combined-state-selectors: true

  Will output selectors like: .element.is-active, set to false to write .element--is-active

• $element-separator: __

• $modifier-separator: --

• $state-prefix: is

  Note that $state-prefix can be overridden with each call to the state mixin, so you can use both --is-active and --has-error using the same configuration:

  @include state('error', 'has') {}

Aliases

Not everyone thinks in the categories of 'block, element, modifier', but many of us still want to write modularized, components-based CSS. There are a couple of aliases included for those who think in terms of components, parent-child / -subcomponents included (And it's totally straightforward to add your own):

@include block('name') {}
    == @include component('name') {}

@include element('name') {}
    == @include child('name') {}
    == @include subcomponent('name') {}
    == @include sub('name') {}

Resources

Some highly recommended reading re CSS structure, decoupling markup and styles, BEM, and why this makes sense:

• Nicolas Gallagher: About HTML semantics and front-end architecture
• Philip Walton: Side Effects in CSS
• BEM official
• Harry Roberts: MindBEMding – getting your head ’round BEM syntax

The MIT License (MIT)

Copyright (c) 2015 Franz Heidl

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.