Function custom

Can be used to create simple custom propSchema. Multiple things can be done inside of a custom propSchema, like deserializing and serializing other (polymorphic) objects, skipping the serialization of something or checking the context of the obj being (de)serialized.

The custom function takes two parameters, the serializer function and the deserializer function.

The serializer function has the signature: (value, key, obj) => void

When serializing the object {a: 1} the serializer function will be called with serializer(1, 'a', {a: 1}).

The deserializer function has the following signature for synchronous processing (value, context, oldValue) => void

For asynchronous processing the function expects the following signature (value, context, oldValue, callback) => void

When deserializing the object {b: 2} the deserializer function will be called with deserializer(2, contextObj) (contextObj reference).

Example

const schemaDefault = createSimpleSchema({
    a: custom(
        v => v + 2,
        v => v - 2
    )
})
serialize(schemaDefault, { a: 4 }) // { "a": 6 }
deserialize(schemaDefault, { "a": 6 }) // { a: 4 }

const schemaWithAsyncProps = createSimpleSchema({
    a: custom(
        v => v + 2,
        (v, context, oldValue, callback) =>
            somePromise(v, context, oldValue)
                .then(result => callback(null, result - 2))
                .catch(err => callback(err))
    )
})
serialize(schemaWithAsyncProps, { a: 4 }) // { "a": 6 }
deserialize(schemaWithAsyncProps, { "a": 6 }, (err, res) => {
  res // { a: 4 }
}