Method executeSteps

packages/db/src/query-engine.ts:94–349

(
    steps: Step[],
    {
      vars,
      viewPlans,
      preparedViews = {},
    }: {
      vars: any;
      viewPlans: Record<string, { steps: Step[] }>;
      preparedViews?: Record<string, ViewEntity[] | ViewEntity>;
    }
  )

  }

  private async executeSteps(
    steps: Step[],
    {
      vars,
      viewPlans,
      preparedViews = {},
    }: {
      vars: any;
      viewPlans: Record<string, { steps: Step[] }>;
      preparedViews?: Record<string, ViewEntity[] | ViewEntity>;
    }
  ): Promise<ViewEntity[] | ViewEntity> {
    // Ensure an entityStack is always present
    vars.entityStack = vars.entityStack || [];
    let results: ViewEntity[] = [];
    let collectionName: string | undefined;
    let candidateIterator:
      | Iterable<ViewEntity>
      | AsyncIterable<ViewEntity>
      | undefined;
    for (const step of steps) {
      switch (step.type) {
        case 'PREPARE_VIEW': {
          const alias = `view_${step.viewId}`;
          // If we've already prepared the view, skip
          if (alias in preparedViews) {
            break;
          }
          const { steps } = viewPlans[step.viewId];
          const viewResults = await this.executeSteps(steps, {
            vars,
            viewPlans,
            preparedViews,
          });
          preparedViews[alias] = viewResults;
          break;
        }
        case 'RESOLVE_FROM_VIEW': {
          const viewKey = `view_${step.viewId}`;
          const view = preparedViews[viewKey];
          if (!view) {
            throw new Error(`View ${step.viewId} not found`);
          }
          if (!Array.isArray(view))
            throw new InvalidResultCardinalityError('many', 'one');
          const boundFilters = bindVariablesInFilters(
            step.filter,
            // When resolving from a view, there should be no other view variables
            // If we error here, possibly re-add slow entity flattening
            vars
          );
          results = [...view];
          for (const filter of boundFilters) {
            results = VAC.resolveQueryFromView(results, filter);
          }
          candidateIterator = results;
          break;
        }