Replaced filter and take/first rxjs operators with find rxjs operator

src/app/submission/form/collection/submission-form-collection.component.ts

@@ -16,7 +16,7 @@ import {
   debounceTime,
   distinctUntilChanged,
   filter,
-  first,
+  find,
   flatMap,
   map,
   mergeMap,
@@ -29,7 +29,7 @@ import { isNullOrUndefined } from 'util';
 import { Collection } from '../../../core/shared/collection.model';
 import { CommunityDataService } from '../../../core/data/community-data.service';
 import { Community } from '../../../core/shared/community.model';
-import { hasValue, isNotEmpty, isEmpty } from '../../../shared/empty.util';
+import { hasValue, isEmpty, isNotEmpty } from '../../../shared/empty.util';
 import { RemoteData } from '../../../core/data/remote-data';
 import { JsonPatchOperationPathCombiner } from '../../../core/json-patch/builder/json-patch-operation-path-combiner';
 import { JsonPatchOperationsBuilder } from '../../../core/json-patch/builder/json-patch-operations-builder';
@@ -107,13 +107,11 @@ export class SubmissionFormCollectionComponent implements OnChanges, OnInit {
       // @TODO replace with search/top browse endpoint
       // @TODO implement community/subcommunity hierarchy
       const listCollection$ = this.communityDataService.findAll().pipe(
-        filter((communities: RemoteData<PaginatedList<Community>>) => isNotEmpty(communities.payload)),
+        find((communities: RemoteData<PaginatedList<Community>>) => isNotEmpty(communities.payload)),
-        first(),
         mergeMap((communities: RemoteData<PaginatedList<Community>>) => communities.payload.page),
         flatMap((communityData: Community) => {
           return communityData.collections.pipe(
-            filter((collections: RemoteData<PaginatedList<Collection>>) => !collections.isResponsePending && collections.hasSucceeded),
+            find((collections: RemoteData<PaginatedList<Collection>>) => !collections.isResponsePending && collections.hasSucceeded),
-            first(),
             mergeMap((collections: RemoteData<PaginatedList<Collection>>) => collections.payload.page),
             filter((collectionData: Collection) => isNotEmpty(collectionData)),
             tap((collectionData: Collection) => {

src/app/submission/sections/form/section-form.component.ts

@@ -2,7 +2,7 @@ import { ChangeDetectorRef, Component, Inject, ViewChild } from '@angular/core';
 import { DynamicFormControlEvent, DynamicFormControlModel } from '@ng-dynamic-forms/core';
 
 import { Observable, Subscription } from 'rxjs';
-import { distinctUntilChanged, filter, flatMap, map, take, tap } from 'rxjs/operators';
+import { distinctUntilChanged, filter, find, flatMap, map, take, tap } from 'rxjs/operators';
 import { TranslateService } from '@ngx-translate/core';
 import { isEqual } from 'lodash';
 
@@ -160,8 +160,7 @@ export class FormSectionComponent extends SectionModelComponent {
 
   checksForErrors(errors: SubmissionSectionError[]) {
     this.formService.isFormInitialized(this.formId).pipe(
-      filter((status: boolean) => status === true && !this.isUpdating),
+      find((status: boolean) => status === true && !this.isUpdating))
-      take(1))
       .subscribe(() => {
         this.sectionService.checkSectionErrors(this.submissionId, this.sectionData.id, this.formId, errors, this.sectionData.errors);
         this.sectionData.errors = errors;

src/app/submission/sections/license/section-license.component.ts

@@ -1,7 +1,7 @@
 import { ChangeDetectorRef, Component, Inject, ViewChild } from '@angular/core';
 
 import { Observable, Subscription } from 'rxjs';
-import { distinctUntilChanged, filter, flatMap, map, take } from 'rxjs/operators';
+import { distinctUntilChanged, filter, find, flatMap, map, take } from 'rxjs/operators';
 import {
   DynamicCheckboxModel,
   DynamicFormControlEvent,
@@ -72,8 +72,7 @@ export class LicenseSectionComponent extends SectionModelComponent {
       this.collectionDataService.findById(this.collectionId).pipe(
         filter((collectionData: RemoteData<Collection>) => isNotUndefined((collectionData.payload))),
         flatMap((collectionData: RemoteData<Collection>) => collectionData.payload.license),
-        filter((licenseData: RemoteData<License>) => isNotUndefined((licenseData.payload))),
+        find((licenseData: RemoteData<License>) => isNotUndefined((licenseData.payload))))
-        take(1))
         .subscribe((licenseData: RemoteData<License>) => {
           this.licenseText = licenseData.payload.text;
 

src/app/submission/sections/upload/accessConditions/accessConditions.component.ts

@@ -1,6 +1,6 @@
 import { Component, Input, OnInit } from '@angular/core';
 
-import { filter, first } from 'rxjs/operators';
+import { find } from 'rxjs/operators';
 
 import { GroupEpersonService } from '../../../../core/eperson/group-eperson.service';
 import { ResourcePolicy } from '../../../../core/shared/resource-policy.model';
@@ -24,8 +24,7 @@ export class AccessConditionsComponent implements OnInit {
     this.accessConditions.forEach((accessCondition: ResourcePolicy) => {
       if (isEmpty(accessCondition.name)) {
         this.groupService.findById(accessCondition.groupUUID).pipe(
-          filter((rd: RemoteData<Group>) => !rd.isResponsePending && rd.hasSucceeded),
+          find((rd: RemoteData<Group>) => !rd.isResponsePending && rd.hasSucceeded))
-          first())
           .subscribe((rd: RemoteData<Group>) => {
             const group: Group = rd.payload;
             const accessConditionEntry = Object.assign({}, accessCondition);

src/app/submission/sections/upload/section-upload.component.ts

@@ -1,7 +1,7 @@
 import { ChangeDetectorRef, Component, Inject } from '@angular/core';
 
 import { combineLatest, Observable } from 'rxjs';
-import { distinctUntilChanged, filter, flatMap, map, reduce, take, tap } from 'rxjs/operators';
+import { distinctUntilChanged, filter, find, flatMap, map, reduce, take, tap } from 'rxjs/operators';
 
 import { SectionModelComponent } from '../models/section.model';
 import { hasValue, isNotEmpty, isNotUndefined, isUndefined } from '../../../shared/empty.util';
@@ -92,17 +92,15 @@ export class UploadSectionComponent extends SectionModelComponent {
         filter((submissionObject: SubmissionObjectEntry) => isUndefined(this.collectionId) || this.collectionId !== submissionObject.collection),
         tap((submissionObject: SubmissionObjectEntry) => this.collectionId = submissionObject.collection),
         flatMap((submissionObject: SubmissionObjectEntry) => this.collectionDataService.findById(submissionObject.collection)),
-        filter((rd: RemoteData<Collection>) => isNotUndefined((rd.payload))),
+        find((rd: RemoteData<Collection>) => isNotUndefined((rd.payload))),
-        take(1),
         tap((collectionRemoteData: RemoteData<Collection>) => this.collectionName = collectionRemoteData.payload.name),
         flatMap((collectionRemoteData: RemoteData<Collection>) => {
           return this.collectionDataService.findByHref(
             (collectionRemoteData.payload as any)._links.defaultAccessConditions
           );
         }),
-        filter((defaultAccessConditionsRemoteData: RemoteData<ResourcePolicy>) =>
+        find((defaultAccessConditionsRemoteData: RemoteData<ResourcePolicy>) =>
           defaultAccessConditionsRemoteData.hasSucceeded),
-        take(1),
         tap((defaultAccessConditionsRemoteData: RemoteData<ResourcePolicy>) => {
           if (isNotEmpty(defaultAccessConditionsRemoteData.payload)) {
             this.collectionDefaultAccessConditions = Array.isArray(defaultAccessConditionsRemoteData.payload)
@@ -125,8 +123,7 @@ export class UploadSectionComponent extends SectionModelComponent {
             if (accessCondition.hasEndDate === true || accessCondition.hasStartDate === true) {
               groups$.push(
                 this.groupService.findById(accessCondition.groupUUID).pipe(
-                  filter((rd: RemoteData<Group>) => !rd.isResponsePending && rd.hasSucceeded),
+                  find((rd: RemoteData<Group>) => !rd.isResponsePending && rd.hasSucceeded))
-                  take(1))
               );
             }
           });

src/app/submission/submission.service.ts

@@ -3,7 +3,7 @@ import { HttpHeaders } from '@angular/common/http';
 import { Router } from '@angular/router';
 
 import { Observable, of as observableOf, Subscription, timer as observableTimer } from 'rxjs';
-import { catchError, distinctUntilChanged, filter, first, map, startWith } from 'rxjs/operators';
+import { catchError, distinctUntilChanged, filter, find, first, map, startWith } from 'rxjs/operators';
 import { Store } from '@ngrx/store';
 import { TranslateService } from '@ngx-translate/core';
 
@@ -123,8 +123,7 @@ export class SubmissionService {
 
   getSubmissionSections(submissionId: string): Observable<SectionDataObject[]> {
     return this.getSubmissionObject(submissionId).pipe(
-      filter((submission: SubmissionObjectEntry) => isNotUndefined(submission.sections) && !submission.isLoading),
+      find((submission: SubmissionObjectEntry) => isNotUndefined(submission.sections) && !submission.isLoading),
-      first(),
       map((submission: SubmissionObjectEntry) => submission.sections),
       map((sections: SubmissionSectionEntry) => {
         const availableSections: SectionDataObject[] = [];
@@ -284,8 +283,7 @@ export class SubmissionService {
 
   retrieveSubmission(submissionId): Observable<RemoteData<SubmissionObject>> {
     return this.restService.getDataById(this.getSubmissionObjectLinkName(), submissionId).pipe(
-      filter((submissionObjects: SubmissionObject[]) => isNotUndefined(submissionObjects)),
+      find((submissionObjects: SubmissionObject[]) => isNotUndefined(submissionObjects)),
-      first(),
       map((submissionObjects: SubmissionObject[]) => new RemoteData(
         false,
         false,