Mongoose save() using native promise - how to catch errors

MongooseJS uses the mpromise library which doesn't have a catch() method. To catch errors you can use the second parameter for then().

var contact = new aircraftContactModel(postVars.contact);contact.save().then(function() {    var aircraft = new aircraftModel(postVars.aircraft);    return aircraft.save();  })  .then(function() {    console.log('aircraft saved')  }, function(err) {    // want to handle errors here  });

UPDATE 1: As of 4.1.0, MongooseJS now allows the specification of which promise implementation to use:

Yup require('mongoose').Promise = global.Promise will make mongoose use native promises. You should be able to use any ES6 promise constructor though, but right now we only test with native, bluebird, and Q

UPDATE 2: If you use mpromise in recent versions of 4.x you will get this deprication warning:

DeprecationWarning: Mongoose: mpromise (mongoose's default promise library) is deprecated

you can extend promise functionality on mongoose with bluebird

Promise = require('bluebird');mongoose.Promise = Promise;

You are probably returning the promise created by method save to handle it somewhere else. If this is the case, you might want to throw the error to a parent promise where you can catch the error. You can achieve it with this:

function saveSchema(doc) {  return doc.save().then(null, function (err) {     throw new Error(err); //Here you are throwing the error to the parent promise  });}function AParentPromise() {  return new Promise(function (accept, reject) {    var doc = new MongoSchema({name: 'Jhon'});    saveSchema(doc).then(function () { // this promise might throw if there is an error      // by being here the doc is already saved    });  }).catch(function(err) {    console.log(err); // now you can catch an error from saveSchema method  });}

I am not really sure if this might be an anti-pattern but this help you to handle your errors in one place.