Encodes event and read model structs to Chronicle's JSON wire format and decodes them back.

This is the single place where the client decides how a struct travels over the wire, so the JSON schema generated by Chronicle.Schemas.JsonSchemaGenerator and the payload that is sent can never drift apart.

Key styles

• :camel — struct field names are rendered as camelCase at every depth (events).
• :identity — struct field names are kept as-is (read models).

Keys of plain maps are data, not field names, and are never transformed.

Value rules

• A Chronicle.Concept is written as its wrapped value.
• Nested structs (and structs inside lists and maps) are written field by field.
• DateTime, NaiveDateTime, Date and Time are written as ISO 8601 strings.
• MapSet is written as a list; non-boolean atoms are written as strings.

Decoding

Decoding is guided by the struct's defaults: a nested struct default decodes the nested object into that struct, a concept default re-wraps the value, a date default parses the string. An integer default receives an integer when the kernel returned a whole-number float (160.0 becomes 160). Fields that hold a list of structs, or a struct that defaults to nil, are declared with the optional types: option of use Chronicle.Events.EventType and use Chronicle.ReadModels.ReadModel:

use Chronicle.Events.EventType,
  id: "order-placed",
  types: [lines: {:list, MyApp.OrderLine}, address: MyApp.Address, labels: :map]