Function resolveData

packages/router/src/operators/resolve_data.ts:28–69

(
  paramsInheritanceStrategy: 'emptyOnly' | 'always',
)

import {DefaultUrlSerializer} from '../url_tree';

export function resolveData(
  paramsInheritanceStrategy: 'emptyOnly' | 'always',
): MonoTypeOperatorFunction<NavigationTransition> {
  return mergeMap((t) => {
    const {
      targetSnapshot,
      guards: {canActivateChecks},
    } = t;

    if (!canActivateChecks.length) {
      return of(t);
    }
    // Iterating a Set in javascript  happens in insertion order so it is safe to use a `Set` to
    // preserve the correct order that the resolvers should run in.
    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set#description
    const routesWithResolversToRun = new Set(canActivateChecks.map((check) => check.route));
    const routesNeedingDataUpdates = new Set<ActivatedRouteSnapshot>();
    for (const route of routesWithResolversToRun) {
      if (routesNeedingDataUpdates.has(route)) {
        continue;
      }
      // All children under the route with a resolver to run need to recompute inherited data.
      for (const newRoute of flattenRouteTree(route)) {
        routesNeedingDataUpdates.add(newRoute);
      }
    }
    let routesProcessed = 0;
    return from(routesNeedingDataUpdates).pipe(
      concatMap((route) => {
        if (routesWithResolversToRun.has(route)) {
          return runResolve(route, targetSnapshot!, paramsInheritanceStrategy);
        } else {
          route.data = getInherited(route, route.parent, paramsInheritanceStrategy).resolve;
          return of(void 0);
        }
      }),
      tap(() => routesProcessed++),
      takeLast(1),
      mergeMap((_) => (routesProcessed === routesNeedingDataUpdates.size ? of(t) : EMPTY)),
    );
  });
}

/**
 *  Returns the `ActivatedRouteSnapshot` tree as an array, using DFS to traverse the route tree.