gistfile1.js

project.createExecutionCDN = function (projectId, extensionDir) {
  var deferred = Q.defer();
  var filePath = path.join(extensionDir, 'project', projectId + '.js');
  var defaultCdnPath = path.join(extensionDir, 'execution.js');

  // verify if exist cdn-project-id.js file
  fs.exists(filePath, function (exists) {

    // Handler if the project cdn not exist.
    if (!exists) {

      fs.readFile(defaultCdnPath, function (readFileError, data) {

        // Handle error
        if (readFileError) {
          deferred.reject('Couldn\'t read file.');
        }

        var customData  = data.toString().replace("%projectId%", projectId);
        fs.writeFile(filePath, customData, function(err) {                
          // Handler error
          if (err) {
            deferred.reject('Couldn\'t write file.');
          } else {
            deferred.resolve(true);
          }
        });
      });
    } else {
      deferred.resolve(true);
    };
  });  
  
  return deferred.promise;
};