code: function ReadZipFile(zip, file) {
      return new Promise((resolve, reject) => {
          var data = "";
          zip.openReadStream(file, function(err, readStream) {
              if (err) {
                  return reject(err);
              }
  
              readStream.on("data", function(chunk) {
                  data += chunk;
              }).on("end", function() {
                  // parse JSON data
                  try {
                      data = JSON.parse(data);
                      return resolve(data);
                  } catch (e) {
                      return reject(`JSON parse error extracting ${file.fileName}: ${e}`);
                  }
              });
          });
      });
  }
docs: static functions