Function getRoots

libs/@blockprotocol/graph/src/stdlib/subgraph/roots.ts:32–50

(
  subgraph: Subgraph<RootType>,
)

 * @param subgraph
 */
export const getRoots = <RootType extends SubgraphRootType>(
  subgraph: Subgraph<RootType>,
): RootType["element"][] =>
  subgraph.roots.map((rootVertexId) => {
    if (!("baseId" in rootVertexId && "revisionId" in rootVertexId)) {
      throw new Error(`Invalid vertex ID: ${JSON.stringify(rootVertexId)}`);
    }

    const root = mustBeDefined(
      (subgraph.vertices as Record<string, Record<string, Vertex>>)[
        rootVertexId.baseId
      ]?.[rootVertexId.revisionId.toString()],
      `roots should have corresponding vertices but ${JSON.stringify(
        rootVertexId,
      )} was missing`,
    );

    return root.inner as RootType["element"];
  });

/**
 * A type-guard that can be used to constrain the generic parameter of `Subgraph` to `DataTypeWithMetadata`.