Allowing custom properties

[matteodem]

What do you think of allowing custom properties to let other packages have the possibility to enhance the Simple Schema with additional information? As an example:

var schema = new SimpleSchema({
    'image' : {
        'type' : String,
        'otherPackage' : {
            'animated' : true
        }
    }
});

I'd also be okay with only one property called "custom" or something where one can define such informations.

[aldeed]

Good question. A few points:

• This is possible using SimpleSchema.extendOptions and mySimpleSchema.validator. These are undocumented, but collection2 uses them to add unique, autoValue, denyInsert, and denyUpdate (and the upcoming index option). Note that validator adds a custom validator to the SimpleSchema instance rather than to all. This is necessary for one of the validations that collection2 does, but in general maybe there should be a SimpleSchema.addValidator or SimpleSchema.addKeyValidator that adds support to all SS instances. I think this is what you're asking for.
• A related idea on my list is to add a custom option that takes a function or array of functions. The functions would return either true or an error type string (same as how mySimpleSchema.validator works now, but user-definable per field).

You can keep this open as a reminder to make these changes.

[aldeed]

Also the custom option would replace valueIsAllowed.

[matteodem]

Thanks for letting me know! I'll have a closer look at the source code then.

[serkandurusoy]

I have hit on a requirement that in fact seems very related to this. Here's a discusson thread that's related, and below is a simplified example of what I'd like available:

BaseSchema = new SimpleSchema({
  name: {
    type: String,
    min: 3
  },
  middleName: {
    type: String,
    optional: true
  },
  lastName: {
    type: String,
    min: 3
  }
});

ExtendedSchema = new SimpleSchema([
  BaseSchema,
  {
    name: {
      min: 5,
      max: 10
    },
    middleName: {
      optional: false
    },
    age: {
      type: Number,
      min: 1,
      max: 100
    }
  }
]);

As you can see, I'd like the ability to override or add to the properties of another schema that's included into this one.

[aldeed]

Yep, we'd just need to _.extend the individual field definitions rather than the schema object as a whole. It's actually related to Meteor-Community-Packages/meteor-collection2#44.

[serkandurusoy]

Hmm, apart from the users collection enhancement, I don't see a specific reason to do this on collection2. I feel, keeping this on simple-schema on the other hand, would also empower those who don't use collection2.

Also contextually speaking, I believe rules about schema validation should reside in the schema object, rather than the collection object.

[aldeed]

Agreed, it would be done on SS, but used by C2 for Meteor.users. I might do the development later today since it should be relatively easy.

[serkandurusoy]

$('<button/>', {text: 'Like :)'}).appendTo(this).click();

[aldeed]

@serkandurusoy, you should now be able to merge/extend schema fields in the way you describe. @matteodem, take a look at Custom Validation. This should address your original issue (and more!).

[serkandurusoy]

Great, thanks. I'll dive right in.