Introduce core/utils/functions.identity()
Constantize random max number
Introduce randomPositiveNumber()
Use randomPositiveNumber as defaultIdGenerator
Rename defaultIdGenerator to randomId
Simplify Store#all() ids mapping to records
Extract Store#idsKey() and #recordKey()
Extract Store#ids() from Store#all()
No more side-effects in unserializeProperties()
Introduce serializeProperties()
Generalize Store#buildRecord()