serialize some async functions in node

serializedemo.js

var init = require('./test/common/init');

// a list of functions that we want to call, in order
var steps = [
  init.createSubscriberTable,
  init.clearSubscriberTable,
  init.createTestSubscribers,
  init.createSubscriberNoticesTable,
  init.clearSubscriberNoticesTable,
  init.createTestSubscriberNotices
];

// we'll be creating some specialized callbacks
var callbacks = [];

// how we create the specialized callbacks
function createCallback(index) {
  return function (err, result) {
    var next = steps[index+1];
    var cb   = callbacks[index+1];
    if (err) {
      console.log('Error: ' + err.message);
    } else if (result) {
      console.log('Result: ' + JSON.stringify(result));
    }
    if (next) {
      next(cb);
    } else {
      console.log('Finished!');
      process.exit(0);
    }
  };
}

// here we create a callback for each function in our list above
for (var i = 0; i < steps.length; i++) {
  callbacks[i] = createCallback(i);
}

// now we invoke the first function with the first callback
// sit back and watch the functions execute one by one...
steps[0](callbacks[0]);