bem-twig-extension/lib/bem-twig-extension.js

BEM Twig extension for Twig.js projects

'use strict';

module.exports = bemTwigExtension;

function bemTwigExtension(Twig) {
  Twig.extendFunction("bem", function(base_class, modifiers = [], blockname = '', extra = [], attributes = '') {
    let classes = [];
    
    // If using a blockname to override default class.
    if (blockname.length) {
        // Set blockname class.
        classes.push(blockname + '__' + base_class);
    
        // Set blockname--modifier classes for each modifier.
        if (modifiers.length && Array.isArray(modifiers)) {
        modifiers.forEach(function(modifier) {
            classes.push(blockname + '__' + base_class + '--' + modifier);
        });
        }
    }
    // If not overriding base class.
    else {
        // Set base class.
        classes.push(base_class);
        // Set base--modifier class for each modifier.
        if (modifiers.length && Array.isArray(modifiers)) {
        modifiers.forEach(function(modifier) {
            classes.push(base_class + '--' + modifier);
        });
        }
    }
    
    // If extra non-BEM classes are added.
    if (extra.length && Array.isArray(extra)) {
        extra.forEach(function(extra_class) {
        classes.push(extra_class);
        });
    }
    
    attributes = 'class="' + classes.join(' ') + '"';
    return attributes;
  });
}