gulp-pngquant

const PLUGIN_NAME = 'gulp-pngquant';
var through = require('through2');
var gutil = require('gulp-util');
var log = gutil.log;
var PluginError = gutil.PluginError;
var pngquant = require('pngquant');

module.exports = function (options) {
  var stream = through.obj(function (file, enc, callback) {
    if (file.isNull()) {
      this.emit('error', new PluginError(PLUGIN_NAME, 'Null not supported!'));
      this.push(file);
      return callback();
    }

    if (file.isBuffer()) {
      this.emit('error', new PluginError(PLUGIN_NAME, 'Buffer not supported!'));
      this.push(file);
      return callback();
    }

    if (file.isStream()) {
      log('options: ', gutil.colors.green(options.join(',')));
      file.contents = file.contents.pipe(new pngquant(options));
      this.push(file);
      return callback();
    }
  });

  return stream;
}