polymer-css-build gulp wrapper

gulp.js

/**
@license
Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
*/

const polycss = require('./');
const Transform = require('stream').Transform;

class PolymerCssBuildTransform extends Transform {
  constructor(options){
    super({objectMode: true});
    this.options = options;
  }
  _transform(file, encoding, callback) {
    if (file.isNull()) {
      return callback(null, file);
    }
    if (file.isStream()) {
      return callback('polymer-css-build does not support streams, sorry');
    }
    if (file.isBuffer()) {
      polycss([
        {
          url: file.path,
          content: file.content.toString('utf-8')
        }
      ], this.options).then(docs => {
        let content = docs[0].content;
        file.content = new Buffer(content);
        callback(null, file);
      })
      .catch(err => {
        callback(err);
      });
    }
  }
}

module.exports = (options) => new PolymerCssBuildTransform(options);