code: function getInputAsStream(input) {
  
      return new Promise(function(resolve, reject) {
  
          if (input.write) {
  
              // already a stream
              resolve(input);
          }
          else {
  
              // read from file
              fs.readFileAsync(input, 'utf-8').then(function(data) {
  
                  // convert file string into stream and pipe into jsdoc-parse
                  var stream = string2stream(data);
  
                  // return stream
                  resolve(stream);
  
              })
              .catch(function(err) {
                  reject(err);
              });
          }
  
      });
  }
docs: Returns a file as a stream
  @param {string} input - path to json/js file containing JSDoc comments
  @returns {Promise} promise to return a stream if the file exists