Some suggestions for improving the asynchronous part of https://github.com/gdiboulder/d3-gapminder.

d3-gapminder-improved.js

// NOTE: The below is pseudo-code. You may need to make some adjustments to
// function signatures to use an asynchronous library like async.js

// these functions can be made truly asynchronous by accepting a callback
// this is preferrably to daisy chaining them, which is too tight a coupling
dv.get.gdp = function(cb) {
	d3.csv('data/gdp.csv', function(error, data) {
		dv.setup.massage(data, 'gdp');
		cb(error, data);
	});
};

dv.get.life = function(cb) {
	d3.csv('data/life.csv', function(error, data) {
		dv.setup.massage(data, 'life');
		cb(error, data);
	});
};

dv.get.population = function(cb) {
	d3.csv('data/population.csv', function(error, data) {
		dv.setup.massage(data, 'population');
		cb(error, data);
	});
};

dv.get.fertility = function(cb) {
	d3.csv('data/fertility.csv', function(error, data) {
		dv.setup.massage(data, 'fertility');
		cb(error, data);
	});
};



// then we can call them sequentially
db.get.gdb(function(error, data) {
  db.get.fertility(function(error, data) {
    db.get.population(function(error, data) {
			db.setup.withData();
    })
  })
})



// or use an async library to eliminate all the nested callbacks
async.series(
	[
		db.get.gdb,
		db.get.fertility,
		db.get.population,
	], 

	// this 'done' callback has the benefit of consolidating errors
	// from the previous functions
	function(err, results) {
		if(err) { console.log(err); }
	  db.setup.withData();
	}
)