callback control - simple way to deal with situations when you have lots of callbacks that need to come back together

cbcontrol.js

/**
 * count is how many callbacks there are in total
 * after to the function to call when all your callbacks have completed
 * return a function that you should call to create your callbacks,
 * optionally passing an individual callback handler
 */
function cbcontrol(count, after) {
	return function(cb) {
		return function() {
			cb && cb.apply(this, arguments);
			if(--count == 0) {
				after();
			}
		};
	};
}

example.js

var sqlite3 = require('sqlite3'),
    db = new sqlite3.Database('::memory::');
function step1() {
    var step1ctr = cbcontrol(3, step2),
    db.run('CREATE TABLE a', step1ctr());
    db.run('CREATE TABLE b', step1ctr());
    db.run('CREATE TABLE c', step1ctr());
}
function step2() {
    var step2ctr = cbcontrol(2, step3);
    db.run('insert into a', step2ctl(function() { console.log(this.lastID); }));
    db.run('insert into b', step2ctl(function() { console.log(this.lastID); }));
}
function step3() {
    ...
}