Mongoose unique validation error type

I had some issues with the approved answer. Namely:

1. this.model('User') didn't work for me.
2. the callback done wasn't working properly.

I resolved those issues by:

  UserSchema.path('email').validate(async (value) => {
    const emailCount = await mongoose.models.User.countDocuments({email: value });
    return !emailCount;
  }, 'Email already exists');

I use async/await which is a personal preference because it is much neater: https://javascript.info/async-await.

Let me know if I got something wrong.

I prefer putting it in path validation mechanisms, like

UserSchema.path('email').validate(function(value, done) {
    this.model('User').count({ email: value }, function(err, count) {
        if (err) {
            return done(err);
        } 
        // If `count` is greater than zero, "invalidate"
        done(!count);
    });
}, 'Email already exists');

Then it'll just get wrapped into ValidationError and will return as first argument when you call validate or save .