1function processData (callback) {
2  fetchData(function (err, data) {
3    if (err) {
4      console.log("An error has occurred. Abort everything!");
5      return callback(err);
6    }
7    data += 1;
8    callback(null, data);
9  });
10}
11
12processData(function (err, data) {
13  if (err) {
14      console.err(err);
15  } else {
16    console.log("Data: " + data);
17  }
18});