D3.js 0 fill null values with d3 series data. See http://stackoverflow.com/a/17057231/436937

gistfile1.js

function insertValues(data, value, dimension, metric, domain) {
	var defaults = {};
	domain.forEach(function(item) {
		var v = {};
		v[dimension] = item;
		v[metric] = value;
		defaults[item] = v;
	});

	_.each(data, function(item) {
		var vals = _.groupBy(item.values, function(i) {
			return i[dimension];
		});
		vals = _.flatten(_.values(_.defaults(vals, defaults)));
		vals = _.sortBy(vals, dimension);
		item.values = vals;
	});
	return data;
}