StackOverflow #38070287 Code Answer

code.js

// http://stackoverflow.com/questions/38070287/nodejs-how-to-manage-username-and-task-management-without-using-external-datab?noredirect=1#comment63578743_38070287 
// On server start load data from file
var storage = {tasks: []};
fs.readFile('database.json', function(err, data) {
  if(err) throw new Error(err);
  storage = JSON.parse(data);
});

// On incoming request
if (query.id == '1') {
  // Add task to variable storage
  storage.tasks.push({taskId: query.id, taskName: query.name});
}
else if (query.id == '2') {
  res.json(storage);
}

// Update database persistent file
fs.writeFile('database.json', JSON.stringify(storage), function (err) {
  if (err) throw new Error('Error while serializing DB'); else console.log('DB updated!');
});