ember-addon with postcss

index.js

/* jshint node: true */
'use strict';

var PostcssCompiler = require('broccoli-postcss');
var path = require('path');
var checker = require('ember-cli-version-checker');
var merge = require('merge');
var mergeTrees = require('broccoli-merge-trees');
var autoprefixer = require('autoprefixer');
var cssnext = require('postcss-cssnext');
var cssnested = require('postcss-nested');
var cssimport = require('postcss-import');

function PostcssPlugin(optionsFn) {
  this.name = 'ember-cli-postcss';
  this.optionsFn = optionsFn;
}

PostcssPlugin.prototype.toTree = function (tree, inputPath, outputPath, inputOptions) {
  var inputTrees = [tree];
  var options = merge({}, this.optionsFn, inputOptions);

  if (options.includePaths) {
    inputTrees = inputTrees.concat(this.options.includePaths);
  }

  var plugins = options.plugins;
  var map = options.map;

  var ext = options.extension || 'css';
  var paths = options.outputPaths;
  var trees = Object.keys(paths).map(function(file) {
    var input = path.join(inputPath, file + '.' + ext);
    var output = paths[file];
    return new PostcssCompiler(inputTrees, input, output, plugins, map);
  });

  return mergeTrees(trees);
};

module.exports = {
  name: 'pcms-ui-v2',

  shouldSetupRegistryInIncluded: function() {
    return !checker.isAbove(this, '0.2.0');
  },

  postcssOptions: function() {
    var env = process.env.EMBER_ENV;
    var options = (this.app && this.app.options && this.app.options.postcssOptions) || {};
    var envConfig = this.project.config(env).postcssOptions;

    if (envConfig) {
      console.warn("Deprecation warning: postcssOptions should be moved to your ember-cli-build");
      merge(options, envConfig);
    }

    // Set defaults if none were passed
    options.map = options.map || {};
    options.plugins = options.plugins || [
      { module: autoprefixer, options: { browsers: ['last 2 version'] } },
      { module: cssimport },
      { module: cssnested },
      { module: cssnext, options: { sourcemap: true } }
    ];
    options.inputFile = options.inputFile || 'app.css';
    options.outputFile = options.outputFile || this.project.name() + '.css';

    return options;
  },

  setupPreprocessorRegistry: function(type, registry) {
   registry.add('css', new PostcssPlugin(this.postcssOptions()));
 },

  included: function included(app) {
    this._super.included.apply(this, arguments);

    // see: https://github.com/ember-cli/ember-cli/issues/3718
    if (typeof app.import !== 'function' && app.app) {
      app = app.app;
    }

    this.app = app;

    if (this.shouldSetupRegistryInIncluded()) {
      this.setupPreprocessorRegistry('parent', app.registry);
    }
  }
};