gistfile1.js

var getNodesAll = function(a, b, c, d) {
  
  url = getURI(a, b, c, d);

  rest.get(url + 'nodes').on('complete', function(result) {
    if (result instanceof Error) {
      console.log('Error:', result.message);
    } else {
      console.log(result);
    }
  });
  
}

This would be the correct way to do this

// function definition
function getNodesAll(a, b, c, d, callback) {
  url = getURI(a, b, c, d);

  rest.get(url + 'nodes').on('complete', function(result) {
    if (result instanceof Error) {
      callback(result);
      return;
    }

    // assumed to be correct
    callback(null, result);
  });
}

// function invocation
getNodesAll('val-a', 'val-b', 'val-c', 'val-d', function (err, result) {
  if (err) {
    // do something about the error?
    throw err;
  }

  console.log('Results', result);
});