Dynamic validation in Mongoose - node.js

Question

I have model, where car property is optional, but there is some property in car nested document, which should be required if User has car, like cartype : {required: true}, but when car is defined.
var UserSchema = new Schema({
email: {
type: 'String',
required: true
},
car: {
carType: {
// should be required if user have car
type: 'Number',
default: TransportType.Car
},
}
})

Answer 1

If there is no default value for carType, we can define one function hasCar to required of carType as below
var UserSchema = new Schema({
email: {
type: 'String',
required: true
},
car: {
carType: {
type: 'Number',
required: hasCar,
//default: TransportType.Car
},
}
});
function hasCar() {
return JSON.stringify(this.car) !== JSON.stringify({});//this.car; && Object.keys(this.car).length > 0;
}
With test codes
var u1 = new UUU({
email: 'test.user1#email.com'
});
u1.save(function(err) {
if (err)
console.log(err);
else
console.log('save u1 successfully');
});
var u2 = new UUU({
email: 'test.user1#email.com',
car: {carType: 23}
});
u2.save(function(err) {
if (err)
console.log(err);
else
console.log('save u2 successfully');
});
Result:
{ "_id" : ObjectId("56db9d21d3fb99340bcd113c"), "email" : "test.user1#email.com", "__v" : 0 }
{ "_id" : ObjectId("56db9d21d3fb99340bcd113d"), "email" : "test.user1#email.com", "car" : { "carType" : 23 }, "__v" : 0 }
However, if there is default value of carType, here maybe one workaround
var UserSchema = new Schema({
email: {
type: 'String',
required: true
},
car: {
carType: {
type: 'Number',
required: hasCar,
default: 1
},
}
});
function hasCar() {
if (JSON.stringify(this.car) === JSON.stringify({carType: 1})) {
this.car = {};
}
return JSON.stringify(this.car) === JSON.stringify({});
}
UserSchema.pre('save', function(next){
// if there is only default value of car, just remove this default carType from car
if (JSON.stringify(this.car) === JSON.stringify({carType: 1})) {
delete this.car;
}
next();
});
With the above test codes, results are
{ "_id" : ObjectId("56db9f73df8599420b7d258a"), "email" : "test.user1#email.com", "car" : null, "__v" : 0 }
{ "_id" : ObjectId("56db9f73df8599420b7d258b"), "email" : "test.user1#email.com", "car" : { "carType" : 23 }, "__v" : 0 }