Function readGraphFromJSON

packages/core/src/Graphs/IO/readGraphFromJSON.ts:30–163

({
  graphJson,
  registry
}: {
  graphJson: GraphJSON;
  registry: IRegistry;
})

// Purpose:
//  - loads a node graph
export function readGraphFromJSON({
  graphJson,
  registry
}: {
  graphJson: GraphJSON;
  registry: IRegistry;
}): GraphInstance {
  const graphName = graphJson?.name || '';
  const graphMetadata = graphJson?.metadata || {};

  let variables: GraphVariables = {};
  let customEvents: GraphCustomEvents = {};

  if ('variables' in graphJson) {
    variables = readVariablesJSON(registry.values, graphJson.variables ?? []);
  }
  if ('customEvents' in graphJson) {
    customEvents = readCustomEventsJSON(
      registry.values,
      graphJson.customEvents ?? []
    );
  }

  const nodesJson = graphJson?.nodes ?? [];

  if (nodesJson.length === 0) {
    Logger.warning('readGraphFromJSON: no nodes specified');
  }

  const graphApi = makeGraphApi({
    ...registry,
    variables,
    customEvents
  });

  const nodes: GraphNodes = {};
  // create new BehaviorNode instances for each node in the json.
  for (let i = 0; i < nodesJson.length; i += 1) {
    const nodeJson = nodesJson[i];
    const node = readNodeJSON({
      graph: graphApi,
      registry,
      nodeJson
    });
    const id = nodeJson.id;

    if (id in nodes) {
      throw new Error(
        `can not create new node with id ${id} as one with that id already exists.`
      );
    }

    nodes[id] = node;
  }

  // connect up the graph edges from BehaviorNode inputs to outputs.  This is required to follow execution
  Object.entries(nodes).forEach(([nodeId, node]) => {
    // initialize the inputs by resolving to the reference nodes.