Function createGraphObserver

packages/y-graph-storage/src/YGraph.ts:90–209

(graph: YGraph<TSchema>)

}

function createGraphObserver<TSchema extends GraphSchema>(graph: YGraph<TSchema>) {
  const { schema, storage } = graph;
  return new Observable<YGraphChange>((o) => {
    const unsubscribers: (() => void)[] = [];
    for (const vertexLabel of Object.keys(schema.vertices)) {
      const collection = storage.getVertexCollectionMap(vertexLabel);
      const observer = (events: Y.YEvent<any>[]) => {
        for (const event of events) {
          const { path } = event;
          if (path.length === 0) {
            if (event instanceof Y.YMapEvent) {
              for (const [uuid, change] of event.changes.keys) {
                if (change.action === "add") {
                  o.next({
                    kind: "vertex.added",
                    id: `${vertexLabel}:${uuid}`,
                  });
                } else if (change.action === "delete") {
                  o.next({
                    kind: "vertex.deleted",
                    id: `${vertexLabel}:${uuid}`,
                  });
                }
              }
            }
          } else if (path.length === 1) {
            for (const [key] of event.changes.keys) {
              if (key.startsWith("@")) {
                continue;
              }
              o.next({
                kind: "vertex.property.set",
                id: `${vertexLabel}:${path[0]!}`,
                property: key,
              });
            }
          } else {
            const [uuid, property, ...path] = event.path as [
              string,
              string,
              ...(string | number)[],
            ];
            if (property.startsWith("@")) {
              continue;
            }
            o.next({
              kind: "vertex.property.changed",
              id: `${vertexLabel}:${uuid}`,
              property,
              path,
              event,
            });
          }
        }
      };
      collection.observeDeep(observer);
      unsubscribers.push(() => collection.unobserveDeep(observer));
    }