Describe a schema which is a union of multiple schemas. This is useful if you need the polymorphic behavior provided by
schema.Values but for non-collection fields.
definition: required An object mapping the definition of the nested entities found within the input array
schemaAttribute: required The attribute on each entity found that defines what schema, per the definition mapping, to use when normalizing. Can be a string or a function. If given a function, accepts the following arguments:
value: The input value of the entity.
parent: The parent object of the input array.
key: The key at which the input array appears on the parent object.
define(definition): When used, the
definitionpassed in will be merged with the original definition passed to the
Unionconstructor. This method tends to be useful for creating circular references in schema.
Note: If your data returns an object that you did not provide a mapping for, the original object will be returned in the result and an entity will not be created.