let AppVersion = new Mongo.Collection('AppVersion'); let AppVersionSchema = new SimpleSchema({ version: { type: Number, optional: false, defaultValue: 0 } }); AppVersion.attachSchema(AppVersionSchema); try { let appVersions = AppVersion.find({}).fetch(); let appVersion; if(!appVersions || appVersions.length == 0) { //This will happen only when first creating a database. appVersion = {version: 0}; appVersion._id = AppVersion.insert(appVersion); } else if(appVersions.length > 1) { //This should never happen. Remove all but the first app version. for(let i = 1; i < appVersions.length; i++) { AppVersion.remove(appVersions[i]._id); } } else { appVersion = appVersions[0]; } } catch(err) { console.log("Caught an error while upgrading the app version: " + err); process.exit(1); }