Make SimpleSchema custom() function reactive

Hi aldeed.

I am currently using the custom() function of SimpleSchema to add a custom validation for many fields of my forms. Basically, i want to add a custom verification to check if a username is available :

    username: {
        type: String,
        regEx: /^[a-z0-9A-Z_]{3,15}$/,
        label: "Username",

        // custom validation for username availability

        custom: function () {
            Meteor.call('accountsIsUsernameAvailable', this.value, function (error, result) {
                if (!result)
                    Session.set("usernameAvailability", "usernameNotAvailable");
                else
                    Session.remove("usernameAvailability");
            });
            return (Session.get("usernameAvailability"));
        }
    }

I am using a method of course because i obviously dont want to publish all the usernames of my database to the client. Because i want a result from these method, i set a callback and the method run asynchronously, and this is where is my issue.

To be sure that i will actually return a result from custom(), u can see in the code example above that i use Session as a reactive data source to make sure the custom function will return the result a soon as it arrive. In fact, there is two return for each excecution of custom(), but i don’t really care.

What i would like to propose, is a way to avoid the use of Session. I prefer in every case to limit the use of Session to do not polluate the namespace. I just wrote my code with Session to test the method inside custom(), but now i am gonna to write my own reactive data source for this purpose, according this tutorial : https://www.eventedmind.com/feed/meteor-build-a-reactive-data-source.

I am wondering if it would be possible to implement such a thing in SimpleSchema custom() function ? I don’t know how it work internally in SimpleSchema, but i guess you are invalidating a field based on the return of custom(). Would it be possible to offer a property this.result inside custom(), let the user fill it with the same way (non-string for success – string for error) and track this with a Deps.Dependency. Then on the change of this property, do the invalidation methodology inside SimpleSchema.

I am maybe wrong about this, if so, forgive me, i’m just sharing my thought because i was thinking of that when i was writting my code.

Regards,

William

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<bold>EDIT:</bold> I don’t think that the context of custom() would be available in the Meteor.Method that have to set the this.result property, but maybe using _.bind would be helpfull in this case, and solve the problem of accessibility.

[aldeed]

In that case, just put my approach into your custom function:

custom: function () {
  if (this.isSet) {
    Meteor.call('accountsIsUsernameAvailable', this.value, function (error, result) {
        if (!result) {
         UserSchema.namedContext('createUserForm').addInvalidKeys([{name: 'username', type: 'notUnique'}]);
        }
    });
  }
}

The custom function doesn’t have to return anything, and when you do return a string, it is essentially identical to calling addInvalidKeys, so this approach is equivalent to returning a custom error string after a short delay.

[thearabbit]

I have problem with onSuccess Hook, it run before custom validate