strata_client/page_store

Typed multi-document store for strata_client apps.

PageStore(page) keys every open document by id over the app's own page sum type (typically a small enum of strata_document.Document variants, one per schema tag). This module never inspects page itself — the app supplies merge and to_json, its own exhaustive functions over every page constructor, so adding a new document kind stays compiler-checked in the app rather than here.

PageStore does not own join state or reconnect behavior; Connection remains the single owner of that. open/close only track which ids this store currently holds a page for; the host pairs open with an explicit strata_client.Join command.

Types

ApplyError

Errors returned by apply_document_event.

pub type ApplyError {
  NotOpen(document_id: String)
  MergeFailed(document_id: String, error: strata_document.DocumentError)
  NotDocumentEvent
}

NotOpen(document_id: String)

The event targets a document id that is not open in this store.

MergeFailed(document_id: String, error: strata_document.DocumentError)

The event carries document state that the app's merge rejected.

NotDocumentEvent

The event is not a document event (Snapshot, RemoteDelta, or Deleted) and carries no document state to apply.

PageStore

Every open document, keyed by id, over the app's own page type.

pub type PageStore(a)

Functions

apply_document_event

Apply a strata_client.Event, returning an explicit error when the event cannot be applied.

Snapshot and RemoteDelta require the document id to be open and the state to merge successfully; otherwise NotOpen or MergeFailed is returned. Deleted requires the id to be open; otherwise NotOpen is returned. Every other event variant returns NotDocumentEvent.

This is the component-facing API. Use apply_event when backward compatibility with no-op-on-error behavior is required.

pub fn apply_document_event(
  PageStore(a),
  strata_client.Event
) -> Result(PageStore(a), ApplyError)

apply_event

Apply a strata_client.Event.

This is a backward-compatible wrapper around apply_document_event. Any error — NotOpen, MergeFailed, or NotDocumentEvent — leaves the store unchanged rather than propagating. Use apply_document_event when the caller must distinguish error cases.

The non-document variants are matched explicitly via apply_document_event, so a future Event variant that should affect document state will force a revisit here rather than silently compiling into a no-op.

pub fn apply_event(
  PageStore(a),
  strata_client.Event
) -> PageStore(a)

close

Close a document. Later events for id are ignored until it is reopened.

pub fn close(
  PageStore(a),
  String
) -> PageStore(a)

get

Look up an open document's page.

pub fn get(
  PageStore(a),
  String
) -> Result(a, Nil)

ids

The ids of every currently open document.

pub fn ids(PageStore(a)) -> List(String)

new

Build an empty store. merge and to_json must be the app's own exhaustive functions over every page constructor.

pub fn new(
  fn(a, json.Json) -> Result(a, strata_document.DocumentError),
  fn(a) -> json.Json
) -> PageStore(a)

open

Open a document, storing initial under id.

This does not send Join; the host pairs it with strata_client.outbound(connection, strata_client.Join(id)).

pub fn open(
  PageStore(a),
  String,
  a
) -> PageStore(a)

update

Apply a local edit.

Returns Some(SendDelta(id, json)) for an open id, where json is the edited page encoded with the app's to_json. Returns None and an unchanged store when id is not open.

pub fn update(
  PageStore(a),
  String,
  fn(a) -> a
) -> #(PageStore(a), option.Option(strata_client.Command))