resolved PR feedback and solved possible bug

src/app/+search-page/search-filters/search-filter/search-filter.component.ts

@@ -129,23 +129,22 @@ export class SearchFilterComponent implements OnInit {
    * @returns {Observable<boolean>} Emits true whenever a given filter config should be shown
    */
   private isActive(): Observable<boolean> {
+    return this.selectedValues$.pipe(
+      switchMap((isActive) => {
+        if (isNotEmpty(isActive)) {
           return observableOf(true);
-    // return this.selectedValues$.pipe(
+        } else {
-    //   switchMap((isActive) => {
+          return this.searchConfigService.searchOptions.pipe(
-    //     if (isNotEmpty(isActive)) {
+            switchMap((options) => {
-    //       return observableOf(true);
+                return this.searchService.getFacetValuesFor(this.filter, 1, options).pipe(
-    //     } else {
+                  filter((RD) => !RD.isLoading),
-    //       return this.searchConfigService.searchOptions.pipe(
+                  map((valuesRD) => {
-    //         switchMap((options) => {
+                    return valuesRD.payload.totalElements > 0
-    //             return this.searchService.getFacetValuesFor(this.filter, 1, options).pipe(
+                  }),)
-    //               filter((RD) => !RD.isLoading),
+              }
-    //               map((valuesRD) => {
+            ))
-    //                 return valuesRD.payload.totalElements > 0
+        }
-    //               }),)
+      }),
-    //           }
+      startWith(true));
-    //         ))
-    //     }
-    //   }),
-    //   startWith(true));
   }
 }

src/app/core/core.effects.ts

@@ -6,6 +6,7 @@ import { AuthEffects } from './auth/auth.effects';
 import { JsonPatchOperationsEffects } from './json-patch/json-patch-operations.effects';
 import { ServerSyncBufferEffects } from './cache/server-sync-buffer.effects';
 import { ObjectUpdatesEffects } from './data/object-updates/object-updates.effects';
+import { RouteEffects } from '../shared/services/route.effects';
 
 export const coreEffects = [
   RequestEffects,
@@ -14,5 +15,6 @@ export const coreEffects = [
   AuthEffects,
   JsonPatchOperationsEffects,
   ServerSyncBufferEffects,
-  ObjectUpdatesEffects
+  ObjectUpdatesEffects,
+  RouteEffects
 ];

src/app/shared/services/route.actions.ts

@@ -10,6 +10,7 @@ export const RouteActionTypes = {
   SET_PARAMETERS: type('dspace/core/route/SET_PARAMETERS'),
   ADD_QUERY_PARAMETER: type('dspace/core/route/ADD_QUERY_PARAMETER'),
   ADD_PARAMETER: type('dspace/core/route/ADD_PARAMETER'),
+  RESET: type('dspace/core/route/RESET'),
 };
 
 /* tslint:disable:max-classes-per-file */
@@ -95,9 +96,21 @@ export class AddParameterAction implements Action {
   }
 }
 
+/**
+ * An ngrx action to reset the route state
+ */
+export class ResetRouteStateAction implements Action {
+  type = RouteActionTypes.RESET;
+}
+
 /* tslint:enable:max-classes-per-file */
 
 /**
  * A type to encompass all RouteActions
  */
-export type RouteAction = SetQueryParametersAction | SetParametersAction | AddQueryParameterAction | AddParameterAction;
+export type RouteActions =
+  SetQueryParametersAction
+  | SetParametersAction
+  | AddQueryParameterAction
+  | AddParameterAction
+  | ResetRouteStateAction;

src/app/shared/services/route.effects.ts

@@ -0,0 +1,23 @@
+import { map } from 'rxjs/operators';
+import { Injectable } from '@angular/core';
+import { Actions, Effect, ofType } from '@ngrx/effects'
+import * as fromRouter from '@ngrx/router-store';
+import { ResetRouteStateAction } from './route.actions';
+
+@Injectable()
+export class RouteEffects {
+  /**
+   * Effect that resets the route state on reroute
+   * @type {Observable<ResetRouteStateAction>}
+   */
+  @Effect() routeChange$ = this.actions$
+    .pipe(
+      ofType(fromRouter.ROUTER_NAVIGATION),
+      map(() => new ResetRouteStateAction())
+    );
+
+  constructor(private actions$: Actions) {
+
+  }
+
+}

src/app/shared/services/route.reducer.ts

@@ -2,22 +2,36 @@ import { Params } from '@angular/router';
 import {
   AddParameterAction,
   AddQueryParameterAction,
-  RouteAction,
+  RouteActions,
   RouteActionTypes, SetParametersAction, SetQueryParametersAction
-} from './route.action';
+} from './route.actions';
 
+/**
+ * Interface to represent the parameter state of a current route in the store
+ */
 export interface RouteState {
   queryParams: Params;
   params: Params;
 }
 
+/**
+ * The initial route state
+ */
 const initialState: RouteState = {
   queryParams: {},
   params: {}
 };
 
-export function routeReducer(state = initialState, action: RouteAction): RouteState {
+/**
+ * Reducer function to save the current route parameters and query parameters in the store
+ * @param state The current or initial state
+ * @param action The action to perform on the state
+ */
+export function routeReducer(state = initialState, action: RouteActions): RouteState {
   switch (action.type) {
+    case RouteActionTypes.RESET: {
+      return initialState
+    }
     case RouteActionTypes.SET_PARAMETERS: {
       return setParameters(state, action as SetParametersAction, 'params');
     }
@@ -36,6 +50,12 @@ export function routeReducer(state = initialState, action: RouteAction): RouteSt
   }
 }
 
+/**
+ * Add a route or query parameter in the store
+ * @param state The current state
+ * @param action The add action to perform on the current state
+ * @param paramType The type of parameter to add: route or query parameter
+ */
 function addParameter(state: RouteState, action: AddParameterAction | AddQueryParameterAction, paramType: string): RouteState {
   const subState = state[paramType];
   const existingValues = subState[action.payload.key] || [];
@@ -43,7 +63,12 @@ function addParameter(state: RouteState, action: AddParameterAction | AddQueryPa
   const newSubstate = Object.assign(subState, { [action.payload.key]: newValues });
   return Object.assign({}, state, { [paramType]: newSubstate });
 }
-
+/**
+ * Set a route or query parameter in the store
+ * @param state The current state
+ * @param action The set action to perform on the current state
+ * @param paramType The type of parameter to set: route or query parameter
+ */
 function setParameters(state: RouteState, action: SetParametersAction | SetQueryParametersAction, paramType: string): RouteState {
   return Object.assign({}, state, { [paramType]: action.payload });
 }

src/app/shared/services/route.service.ts

@@ -14,23 +14,44 @@ import { isEqual } from 'lodash';
 
 import { AddUrlToHistoryAction } from '../history/history.actions';
 import { historySelector } from '../history/selectors';
-import { SetParametersAction, SetQueryParametersAction } from './route.action';
+import { SetParametersAction, SetQueryParametersAction } from './route.actions';
 import { CoreState } from '../../core/core.reducers';
 import { hasValue } from '../empty.util';
 import { coreSelector } from '../../core/core.selectors';
 
+/**
+ * Selector to select all route parameters from the store
+ */
 export const routeParametersSelector = createSelector(
   coreSelector,
   (state: CoreState) => state.route.params
 );
+
+/**
+ * Selector to select all query parameters from the store
+ */
 export const queryParametersSelector = createSelector(
   coreSelector,
   (state: CoreState) => state.route.queryParams
 );
 
+/**
+ * Selector to select a specific route parameter from the store
+ * @param key The key of the parameter
+ */
 export const routeParameterSelector = (key: string) => parameterSelector(key, routeParametersSelector);
+
+/**
+ * Selector to select a specific query parameter from the store
+ * @param key The key of the parameter
+ */
 export const queryParameterSelector = (key: string) => parameterSelector(key, queryParametersSelector);
 
+/**
+ * Function to select a specific parameter from the store
+ * @param key The key to look for
+ * @param paramsSelector The selector that selects the parameters to search in
+ */
 export function parameterSelector(key: string, paramsSelector: (state: CoreState) => Params): MemoizedSelector<CoreState, string> {
   return createSelector(paramsSelector, (state: Params) => {
     if (hasValue(state)) {