code: function createStream() {
    var firstChunk = true;
  
    var stream = through(function transform(chunk, encoding, next) {
      if (!firstChunk) return next(null, chunk);
  
      firstChunk = false;
  
      var regex = /^(.+?)(\(function\(\)\{)/
        , pattern;
  
      chunk = chunk.toString().replace(regex, function replacer(match, p1, p2) {
        pattern = p1;
        return p2;
      });
  
      this.push(prune(pattern) + chunk);
      next();
    });
  
    stream.label = 'prune-umd';
    return stream;
  }
docs: Create a transform stream.
  
  @returns {Stream} Transform stream
  @api private