UFAL/Updated the no file preview message and refactored some code (#837)

* Updated the no file preview message and refactored some code.

* Added a non null check when accessing the object properties and the message is refactored.

Author: milanmajchrak

src/app/item-page/simple/field-components/preview-section/file-description/file-description.component.html

@@ -61,9 +61,8 @@
       </div>
       <div [style]="'max-height: 500px; padding: 0px; overflow: scroll'" class="panel-body">
         <ul class="treeview collapse show">
-          <!-- Loading Spinner -->
-          <div *ngIf="fileInput.fileInfo.length === 0" class="d-flex justify-content-center align-items-center my-3">
-            <div>{{'item.preview.no-preview' | translate}}
+          <div *ngIf="hasNoPreview()" class="d-flex justify-content-center align-items-center my-3">
+            <div>{{ 'item.preview.no-preview' | translate }}
               <a *ngIf="emailToContact" [href]="'mailto:' + emailToContact" class="email-text">{{ emailToContact }}</a>
             </div>
           </div>

src/app/item-page/simple/field-components/preview-section/file-description/file-description.component.ts

@@ -3,6 +3,7 @@ import { MetadataBitstream } from 'src/app/core/metadata/metadata-bitstream.mode
 import { HALEndpointService } from '../../../../../core/shared/hal-endpoint.service';
 import { Router } from '@angular/router';
 import { ConfigurationDataService } from '../../../../../core/data/configuration-data.service';
+import { getFirstSucceededRemoteData } from '../../../../../core/shared/operators';
 
 const allowedPreviewFormats = ['text/plain', 'text/html', 'application/zip', 'application/x-tar'];
 @Component({
@@ -24,8 +25,10 @@ export class FileDescriptionComponent implements OnInit {
               private configService: ConfigurationDataService) { }
 
   ngOnInit(): void {
-    this.configService.findByPropertyName('lr.help.mail').subscribe(remoteData => {
-      this.emailToContact = remoteData.payload.values[0];
+    this.configService.findByPropertyName('lr.help.mail')
+      .pipe(getFirstSucceededRemoteData())
+      .subscribe(remoteData => {
+      this.emailToContact = remoteData?.payload?.values?.[0];
     });
   }
 
@@ -61,4 +64,8 @@ export class FileDescriptionComponent implements OnInit {
     return format === 'application/zip' || format === 'application/x-tar';
   }
 
+  hasNoPreview() {
+    // this.fileInput.fileInfo.length === 0 means that the file has no preview
+    return this.fileInput?.fileInfo?.length === 0;
+  }
 }

src/app/item-page/simple/field-components/preview-section/preview-section.component.ts

@@ -28,7 +28,7 @@ export class PreviewSectionComponent implements OnInit {
         this.listOfFiles.next(data);
       });
     this.configService.findByPropertyName('lr.help.mail')?.subscribe(remoteData => {
-      this.emailToContact = remoteData.payload.values[0];
+      this.emailToContact = remoteData.payload?.values?.[0];
     });
   }
 

src/assets/i18n/cs.json5

@@ -3382,8 +3382,8 @@
   "item.preview.authors.et.al": "; et al.",
   // "item.preview.loading-files": "Loading files... This may take a few seconds as file previews are being generated. If the process takes too long, please contact the system administrator",
   "item.preview.loading-files": "Načítání souborů... Může to trvat několik sekund, protože se generují náhledy souborů. Pokud proces trvá příliš dlouho, kontaktujte prosím správce systému",
-  // "item.preview.no-preview": "The file preview wasn't successfully generated, please contact the system administrator",
-  "item.preview.no-preview": "Náhled souboru nebyl úspěšně vygenerován, kontaktujte prosím správce systému",
+  // "item.preview.no-preview": "The file preview has not been generated yet. Please try again later or contact the system administrator",
+  "item.preview.no-preview": "Náhled souboru zatím nebyl vygenerován. Zkuste to prosím znovu později, nebo kontaktujte správce systému",
   // "item.refbox.modal.copy.instruction": ["Press", "ctrl + c", "to copy"],
   "item.refbox.modal.copy.instruction": ["Stiskněte", "ctrl + c", "pro kopírování"],
   // "item.refbox.modal.submit": "Ok",

src/assets/i18n/en.json5

@@ -2834,7 +2834,7 @@
 
   "item.preview.loading-files": "Loading files... This may take a few seconds as file previews are being generated. If the process takes too long, please contact the system administrator",
 
-  "item.preview.no-preview": "The file preview wasn't successfully generated, please contact the system administrator",
+  "item.preview.no-preview": "The file preview has not been generated yet. Please try again later or contact the system administrator",
 
   "item.refbox.modal.copy.instruction": ["Press", "ctrl + c", "to copy"],