client, server: convert chained null checks to optional chaining

client/src/javascript/components/general/ListViewport.tsx

@@ -249,7 +249,7 @@ class ListViewport extends React.Component<ListViewportProps, ListViewportStates
           ref={(ref) => {
             this.topSpacerRef = ref;
 
-            if (itemHeight == null && this.topSpacerRef != null && this.topSpacerRef.nextSibling != null) {
+            if (itemHeight == null && this.topSpacerRef?.nextSibling != null) {
               this.setState({
                 itemHeight: (this.topSpacerRef.nextSibling as HTMLLIElement).offsetHeight,
               });

client/src/javascript/components/modals/add-torrents-modal/AddTorrentsByFile.tsx

@@ -106,7 +106,7 @@ class AddTorrentsByFile extends React.Component<WrappedComponentProps, AddTorren
       const reader = new FileReader();
       reader.onload = (e) => {
         this.setState((state) => {
-          if (e.target != null && e.target.result != null && typeof e.target.result === 'string') {
+          if (e.target?.result != null && typeof e.target.result === 'string') {
             return {
               errors: nextErrorsState,
               files: state.files.concat({

client/src/javascript/components/modals/feeds-modal/DownloadRulesTab.tsx

@@ -488,7 +488,7 @@ class DownloadRulesTab extends React.Component<DownloadRulesTabProps, DownloadRu
     if (this.state.errors != null) {
       errors = Object.keys(this.state.errors).map((error) => {
         const errorID = error as ValidatedFields;
-        if (this.state.errors == null || this.state.errors[errorID] == null) {
+        if (this.state.errors?.[errorID] == null) {
           return null;
         }
         return (

client/src/javascript/components/modals/feeds-modal/FeedsTab.tsx

@@ -426,7 +426,7 @@ class FeedsTab extends React.Component<FeedsTabProps, FeedsTabStates> {
       if (formData != null) {
         if (currentFeed === defaultFeed) {
           FeedsStoreClass.addFeed(formData);
-        } else if (currentFeed != null && currentFeed._id != null) {
+        } else if (currentFeed?._id != null) {
           FeedsStoreClass.modifyFeed(currentFeed._id, formData);
         }
       }
@@ -550,7 +550,7 @@ class FeedsTab extends React.Component<FeedsTabProps, FeedsTabStates> {
     if (this.state.errors != null) {
       errors = Object.keys(this.state.errors).map((error) => {
         const errorID = error as ValidatedFields;
-        if (this.state.errors == null || this.state.errors[errorID] == null) {
+        if (this.state.errors?.[errorID] == null) {
           return null;
         }
         return (

client/src/javascript/components/sidebar/TransferRateDetails.tsx

@@ -70,7 +70,7 @@ class TransferRateDetails extends React.Component<TransferRateDetailsProps> {
       'is-visible': inspectorPoint != null && options.showHoverDuration,
     });
 
-    if (inspectorPoint != null && inspectorPoint.nearestTimestamp != null) {
+    if (inspectorPoint?.nearestTimestamp != null) {
       const currentTime = dayjs(Date.now());
       const durationSummary = formatUtil.secondsToDuration(
         dayjs.duration(currentTime.diff(dayjs(inspectorPoint.nearestTimestamp))).asSeconds(),

client/src/javascript/components/torrent-list/TorrentList.tsx

@@ -214,7 +214,7 @@ class TorrentList extends React.Component<TorrentListProps, TorrentListStates> {
     files.forEach((file) => {
       const reader = new FileReader();
       reader.onload = (e) => {
-        if (e.target != null && e.target.result != null && typeof e.target.result === 'string') {
+        if (e.target?.result != null && typeof e.target.result === 'string') {
           callback(e.target.result.split('base64,')[1]);
         }
       };

client/src/javascript/ui/components/Select.tsx

@@ -97,7 +97,7 @@ export default class Select extends Component<SelectProps, SelectStates> {
         return (child as SelectItem).props.id != null;
       }) as SelectItem;
 
-      if (item != null && item.props.id != null) {
+      if (item?.props?.id != null) {
         return item.props.id;
       }
     }

client/src/javascript/util/selectionTree.ts

@@ -48,7 +48,7 @@ const applySelection = (
 
   // Change happens
   if (recursiveDepth === depth - 1) {
-    if (type === 'file' && tree.files != null && tree.files[currentPath] != null) {
+    if (type === 'file' && tree.files?.[currentPath] != null) {
       const files = {
         ...tree.files,
         [currentPath]: {

server/models/Users.ts

@@ -55,7 +55,7 @@ class Users {
       }
 
       // Wrong data provided
-      if (credentials == null || credentials.password == null) {
+      if (credentials?.password == null) {
         return callback(false, null, new Error());
       }
 
@@ -120,7 +120,7 @@ class Users {
       }
 
       // Username not found.
-      if (user == null || user._id == null) {
+      if (user?._id == null) {
         return callback(null, new Error('User not found.'));
       }
 

server/services/taxonomyService.ts

@@ -28,7 +28,7 @@ class TaxonomyService extends BaseService<TaxonomyServiceEvents> {
     this.handleProcessTorrentListEnd = this.handleProcessTorrentListEnd.bind(this);
 
     this.onServicesUpdated = () => {
-      if (this.services == null || this.services.clientGatewayService == null) {
+      if (this.services?.clientGatewayService == null) {
         return;
       }
 
@@ -41,7 +41,7 @@ class TaxonomyService extends BaseService<TaxonomyServiceEvents> {
   }
 
   destroy() {
-    if (this.services == null || this.services.clientGatewayService == null) {
+    if (this.services?.clientGatewayService == null) {
       return;
     }
 

server/services/torrentService.ts

@@ -29,7 +29,7 @@ class TorrentService extends BaseService<TorrentServiceEvents> {
     this.handleFetchTorrentListError = this.handleFetchTorrentListError.bind(this);
 
     this.onServicesUpdated = () => {
-      if (this.services == null || this.services.clientGatewayService == null) {
+      if (this.services?.clientGatewayService == null) {
         return;
       }