a.js

var mongo = require('./lib/mongo');
var logger = require("./lib/log").getLogger('data-rebuild-schedule');

var appConf = require('./etc').application;

logger.debug("Beginning rebuild data...");

mongo.remove('user-days', {}, function (err, r) {
	if (err) {
		logger.error("Clear data error: %s", err);
	} else {
		mongo.find('users', {}, {}, function (err, ur) {
			if (err) {
				logger.error("Rebuild data error: %s", err);
			} else {
				var newData = [];
				ur.forEach(function (user) {
					newData.push({ "name": user.name, "available": [], "cars": [], "version": 1});
				});

				mongo.save('user-days', newData, function (err, sr) {
					if (err) {
						logger.error("Saving new data error: %s", err);
					} else {
						logger.debug("Saved new data successfully.");
					}
				});
			}
		});
	}
});