View Source Chord.Delta.Formatter.Default (Chord v0.1.2)

Default implementation for delta formatting.

This module provides a straightforward and opinionated way to format deltas into a list of maps. Each map describes a change to a specific key in the context, including metadata such as the action performed (e.g., :added, :modified, :removed) and the associated context_id.

The formatting is intended to be extensible, allowing developers to substitute this formatter with a custom implementation by defining their own module and setting it in the application configuration.

Example 

iex> delta = %{
...>   a: %{action: :added, value: 1},
...>   b: %{action: :modified, old_value: 2, value: 3},
...>   c: %{action: :removed}
...> }
iex> context_id = "game:1"
iex> Chord.Delta.Formatter.Default.format(delta, context_id)
[
  %{key: :a, action: :added, value: 1, context: "game:1"},
  %{key: :b, action: :modified, old_value: 2, value: 3, context: "game:1"},
  %{key: :c, action: :removed, context: "game:1"}
]

Summary

Functions

format(delta, context_id)

Formats the given delta into a standardized list of maps.

Functions

format(delta, context_id)

@spec format(map(), any()) :: [map()]

Formats the given delta into a standardized list of maps.

This implementation adds the context_id to each change and formats changes as follows:

  • For :added, includes the new value.
  • For :modified, includes both the old_value and the new value.
  • For :removed, includes only the key and context_id.

Parameters

  • delta (map): The delta map representing changes to the context.
  • context_id (any): The context ID to associate with each change.

Returns

  • (list of maps): A list of formatted changes.

Example 

iex> delta = %{
...>   a: %{action: :added, value: 1},
...>   b: %{action: :modified, old_value: 2, value: 3},
...>   c: %{action: :removed}
...> }
iex> Chord.Delta.Formatter.Default.format(delta, "game:1")
[
  %{key: :a, action: :added, value: 1, context: "game:1"},
  %{key: :b, action: :modified, old_value: 2, value: 3, context: "game:1"},
  %{key: :c, action: :removed, context: "game:1"}
]