teach ts type gen how to handle nullable return types

backend/FwLite/FwLiteShared/Events/JsEventListener.cs

@@ -69,7 +69,6 @@ public JsEventListener(ILogger<JsEventListener> logger, GlobalEventBus globalEve
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<IFwEvent | null>")]
     public ValueTask<IFwEvent?> LastEvent(FwEventType type)
     {
         return ValueTask.FromResult(_globalEventBus.GetLastEvent(type));

backend/FwLite/FwLiteShared/Services/IPreferencesService.cs

@@ -10,7 +10,6 @@ namespace FwLiteShared.Services;
 public interface IPreferencesService
 {
     [JSInvokable]
-    [TsFunction(Type = "Promise<string | null>")]
     string? Get(string key);
     [JSInvokable]
     void Set(string key, string value);

backend/FwLite/FwLiteShared/Services/MiniLcmJsInvokable.cs

@@ -86,14 +86,12 @@ public ValueTask<CustomView[]> GetCustomViews()
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<ICustomView | null>")]
     public Task<CustomView?> GetCustomView(Guid id)
     {
         return _wrappedApi.GetCustomView(id);
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<IComplexFormType | null>")]
     public Task<ComplexFormType?> GetComplexFormType(Guid id)
     {
         return _wrappedApi.GetComplexFormType(id);
@@ -139,35 +137,30 @@ public Task<Entry[]> SearchEntries(string query, QueryOptions? options = null)
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<IEntry | null>")]
     public Task<Entry?> GetEntry(Guid id)
     {
         return Task.Run(async () => await _wrappedApi.GetEntry(id));
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<ISense | null>")]
     public Task<Sense?> GetSense(Guid entryId, Guid id)
     {
         return _wrappedApi.GetSense(entryId, id);
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<IPartOfSpeech | null>")]
     public Task<PartOfSpeech?> GetPartOfSpeech(Guid id)
     {
         return _wrappedApi.GetPartOfSpeech(id);
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<ISemanticDomain | null>")]
     public Task<SemanticDomain?> GetSemanticDomain(Guid id)
     {
         return _wrappedApi.GetSemanticDomain(id);
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<IExampleSentence | null>")]
     public Task<ExampleSentence?> GetExampleSentence(Guid entryId, Guid senseId, Guid id)
     {
         return _wrappedApi.GetExampleSentence(entryId, senseId, id);
@@ -286,7 +279,6 @@ public ValueTask<CommentThread[]> GetCommentThreads(SubjectType subjectType, Gui
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<ICommentThread | null>")]
     public Task<CommentThread?> GetCommentThread(Guid id)
     {
         return _wrappedApi.GetCommentThread(id);
@@ -299,7 +291,6 @@ public ValueTask<UserComment[]> GetUserComments(Guid threadId)
     }
 
     [JSInvokable]
-    [TsFunction(Type = "Promise<IUserComment | null>")]
     public Task<UserComment?> GetUserComment(Guid id)
     {
         return _wrappedApi.GetUserComment(id);
@@ -531,7 +522,7 @@ public async Task DeletePicture(Guid entryId, Guid senseId, Guid pictureId)
     }
 
     [JSInvokable]
-    public async Task<ReadFileResponseJs?> GetFileStream(string mediaUri, bool downloadIfMissing)
+    public async Task<ReadFileResponseJs> GetFileStream(string mediaUri, bool downloadIfMissing)
     {
         var result = await _wrappedApi.GetFileStream(new MediaUri(mediaUri), downloadIfMissing);
         var stream = result.Stream is null ? null : new DotNetStreamReference(result.Stream);

backend/FwLite/FwLiteShared/Services/ProjectServicesProvider.cs

@@ -39,10 +39,10 @@ public async Task DisposeService(DotNetObjectReference<IAsyncDisposable> service
     }
 
     [JSInvokable]
-    public Task<string?> TryGetCrdtProjectName(string code)
+    public string? TryGetCrdtProjectName(string code)
     {
         var crdtProject = crdtProjectsService.GetProject(code);
-        return Task.FromResult(crdtProject?.Data?.Name);
+        return crdtProject?.Data?.Name;
     }
 
     [JSInvokable]

backend/FwLite/FwLiteShared/Services/UpdateService.cs

@@ -7,7 +7,6 @@ namespace FwLiteShared.Services;
 public class UpdateService(UpdateChecker updateChecker)
 {
     [JSInvokable]
-    [TsFunction(Type = "Promise<IAvailableUpdate | null>")]
     public Task<AvailableUpdate?> CheckForUpdates()
     {
         return Task.Run(async () => await updateChecker.CheckForUpdate());

backend/FwLite/FwLiteShared/TypeGen/ReinforcedFwLiteTypingConfig.cs

@@ -28,6 +28,7 @@
 using MiniLcm.Media;
 using MediaFile = MiniLcm.Media.MediaFile;
 using Microsoft.Extensions.Logging;
+using Reinforced.Typings.Generators;
 using SIL.Harmony.Changes;
 using SIL.Harmony.Resource;
 
@@ -228,6 +229,7 @@ private static void ConfigureFwLiteSharedTypes(ConfigurationBuilder builder)
 
     private static MethodExportBuilder AlwaysReturnPromise(this MethodExportBuilder exportBuilder)
     {
+        exportBuilder.WithCodeGenerator<NullableMethodReturnBuilder>();
         var isUpdatePatchMethod = exportBuilder.Member.GetParameters()
             .Any(p => p.ParameterType.IsGenericType &&
                       p.ParameterType.GetGenericTypeDefinition() == typeof(UpdateObjectInput<>));
@@ -310,4 +312,40 @@ public override void Visit(RtImport node)
             base.Visit(node);
         }
     }
+
+    /// <summary>
+    /// introspects the return type of a method to determine if it is nullable and modifies the return type to be T | undefined
+    /// before Task<T?> -> Promise<T> after Promise<T | undefined>
+    /// </summary>
+    internal class NullableMethodReturnBuilder : MethodCodeGenerator
+    {
+        private static NullabilityInfoContext _nullabilityInfoContext = new();
+        protected override void GetFunctionNameAndReturnType(MethodInfo element, TypeResolver resolver, out string name, out RtTypeName type)
+        {
+            base.GetFunctionNameAndReturnType(element, resolver, out name, out type);
+            if (type is RtAsyncType {TypeNameOfAsync: RtSimpleTypeName asyncResolveType})
+            {
+                var nullabilityInfo = _nullabilityInfoContext.Create(element.ReturnParameter);
+                var mayBeNull = false;
+                //some methods return Task<T> but some just return T and we force them to always show as Promise<T>
+                //but here we need to know which as we're looking at the underlying type
+                if (element.ReturnType.IsGenericType &&
+                    (element.ReturnType.GetGenericTypeDefinition() == typeof(Task<>)
+                     || element.ReturnType.GetGenericTypeDefinition() == typeof(ValueTask<>)))
+                {
+                    mayBeNull = (nullabilityInfo.GenericTypeArguments.FirstOrDefault()?.ReadState ?? NullabilityState.Nullable) == NullabilityState.Nullable;
+                }
+                else
+                {
+                    mayBeNull = nullabilityInfo.ReadState == NullabilityState.Nullable;
+                }
+
+                if (mayBeNull)
+                {
+                    type = new RtAsyncType(new RtSimpleTypeName(asyncResolveType.TypeName + " | undefined"));
+                }
+            }
+
+        }
+    }
 }

frontend/viewer/src/home/ServersList.svelte

@@ -29,7 +29,8 @@
 
   async function refreshServerProjects(server: ILexboxServer, force: boolean = false) {
     loadingServerProjects = server.id;
-    remoteProjects[server.id] = await projectsService.serverProjects(server.id, force);
+    const projects = await projectsService.serverProjects(server.id, force);
+    if (projects) remoteProjects[server.id] = projects;
     remoteProjects = remoteProjects;
     loadingServerProjects = undefined;
   }

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Events/IJsEventListener.ts

@@ -8,7 +8,7 @@ import type {FwEventType} from './FwEventType';
 
 export interface IJsEventListener
 {
-	nextEventAsync() : Promise<IFwEvent>;
-	lastEvent(type: FwEventType) : Promise<IFwEvent | null>;
+	nextEventAsync() : Promise<IFwEvent | undefined>;
+	lastEvent(type: FwEventType) : Promise<IFwEvent | undefined>;
 }
 /* eslint-enable */

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Projects/ICombinedProjectsService.ts

@@ -13,7 +13,7 @@ export interface ICombinedProjectsService
 {
 	supportsFwData() : Promise<boolean>;
 	remoteProjects() : Promise<IServerProjects[]>;
-	serverProjects(serverId: string, forceRefresh: boolean) : Promise<IServerProjects>;
+	serverProjects(serverId: string, forceRefresh: boolean) : Promise<IServerProjects | undefined>;
 	localProjects() : Promise<IProjectModel[]>;
 	downloadProjectByCode(code: string, server: ILexboxServer, userRole?: UserProjectRole) : Promise<DownloadProjectByCodeResult>;
 	downloadProject(project: IProjectModel) : Promise<void>;

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IHistoryServiceJsInvokable.ts

@@ -18,7 +18,7 @@ export interface IHistoryServiceJsInvokable
 	projectActivity(skip: number, take: number, authorFilterKeys?: string[], changeTypeKeys?: string[], sort?: ActivitySort) : Promise<IProjectActivity[]>;
 	listActivityAuthors() : Promise<IActivityAuthor[]>;
 	listActivityChangeTypes() : Promise<IActivityChangeType[]>;
-	getSnapshot(snapshotId: string) : Promise<IObjectSnapshot>;
+	getSnapshot(snapshotId: string) : Promise<IObjectSnapshot | undefined>;
 	getHistory(entityId: string) : Promise<IHistoryLineItem[]>;
 	loadChangeContext(commitId: string, changeIndex: number) : Promise<IChangeContext>;
 }

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmJsInvokable.ts

@@ -15,6 +15,8 @@ import type {IFilterQueryOptions} from '../../MiniLcm/IFilterQueryOptions';
 import type {IIndexQueryOptions} from '../../MiniLcm/IIndexQueryOptions';
 import type {IEntry} from '../../MiniLcm/Models/IEntry';
 import type {IQueryOptions} from '../../MiniLcm/IQueryOptions';
+import type {ISense} from '../../MiniLcm/Models/ISense';
+import type {IExampleSentence} from '../../MiniLcm/Models/IExampleSentence';
 import type {IWritingSystem} from '../../MiniLcm/Models/IWritingSystem';
 import type {WritingSystemType} from '../../MiniLcm/Models/WritingSystemType';
 import type {ICommentThread} from '../../MiniLcm/Models/ICommentThread';
@@ -23,8 +25,6 @@ import type {IUserComment} from '../../MiniLcm/Models/IUserComment';
 import type {ThreadStatus} from '../../MiniLcm/Models/ThreadStatus';
 import type {ICreateEntryOptions} from '../../MiniLcm/ICreateEntryOptions';
 import type {IComplexFormComponent} from '../../MiniLcm/Models/IComplexFormComponent';
-import type {ISense} from '../../MiniLcm/Models/ISense';
-import type {IExampleSentence} from '../../MiniLcm/Models/IExampleSentence';
 import type {IPicture} from '../../MiniLcm/Models/IPicture';
 import type {IReadFileResponseJs} from './IReadFileResponseJs';
 import type {IUploadFileResponse} from '../../MiniLcm/Media/IUploadFileResponse';
@@ -39,18 +39,18 @@ export interface IMiniLcmJsInvokable
 	getSemanticDomains() : Promise<ISemanticDomain[]>;
 	getComplexFormTypes() : Promise<IComplexFormType[]>;
 	getCustomViews() : Promise<ICustomView[]>;
-	getCustomView(id: string) : Promise<ICustomView | null>;
-	getComplexFormType(id: string) : Promise<IComplexFormType | null>;
+	getCustomView(id: string) : Promise<ICustomView | undefined>;
+	getComplexFormType(id: string) : Promise<IComplexFormType | undefined>;
 	getMorphTypes() : Promise<IMorphType[]>;
 	countEntries(query?: string, options?: IFilterQueryOptions) : Promise<number>;
 	getEntryIndex(id: string, query?: string, options?: IIndexQueryOptions) : Promise<number>;
 	getEntries(options?: IQueryOptions) : Promise<IEntry[]>;
 	searchEntries(query: string, options?: IQueryOptions) : Promise<IEntry[]>;
-	getEntry(id: string) : Promise<IEntry | null>;
-	getSense(entryId: string, id: string) : Promise<ISense | null>;
-	getPartOfSpeech(id: string) : Promise<IPartOfSpeech | null>;
-	getSemanticDomain(id: string) : Promise<ISemanticDomain | null>;
-	getExampleSentence(entryId: string, senseId: string, id: string) : Promise<IExampleSentence | null>;
+	getEntry(id: string) : Promise<IEntry | undefined>;
+	getSense(entryId: string, id: string) : Promise<ISense | undefined>;
+	getPartOfSpeech(id: string) : Promise<IPartOfSpeech | undefined>;
+	getSemanticDomain(id: string) : Promise<ISemanticDomain | undefined>;
+	getExampleSentence(entryId: string, senseId: string, id: string) : Promise<IExampleSentence | undefined>;
 	createWritingSystem(type: WritingSystemType, writingSystem: IWritingSystem) : Promise<IWritingSystem>;
 	updateWritingSystem(before: IWritingSystem, after: IWritingSystem) : Promise<IWritingSystem>;
 	createPartOfSpeech(partOfSpeech: IPartOfSpeech) : Promise<IPartOfSpeech>;
@@ -66,9 +66,9 @@ export interface IMiniLcmJsInvokable
 	updateCustomView(customView: ICustomView) : Promise<ICustomView>;
 	deleteCustomView(id: string) : Promise<void>;
 	getCommentThreads(subjectType: SubjectType, subjectId: string, includeComments?: boolean) : Promise<ICommentThread[]>;
-	getCommentThread(id: string) : Promise<ICommentThread | null>;
+	getCommentThread(id: string) : Promise<ICommentThread | undefined>;
 	getUserComments(threadId: string) : Promise<IUserComment[]>;
-	getUserComment(id: string) : Promise<IUserComment | null>;
+	getUserComment(id: string) : Promise<IUserComment | undefined>;
 	getUnreadComments(threadId?: string) : Promise<IUserComment[]>;
 	getUnreadCommentsForSubject(subjectType: SubjectType, subjectId: string) : Promise<IUserComment[]>;
 	countUnreadComments(threadId?: string) : Promise<number>;

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IPreferencesService.ts

@@ -5,7 +5,7 @@
 
 export interface IPreferencesService
 {
-	get(key: string) : Promise<string | null>;
+	get(key: string) : Promise<string | undefined>;
 	set(key: string, value: string) : Promise<void>;
 	remove(key: string) : Promise<void>;
 }

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IProjectServicesProvider.ts

@@ -10,7 +10,7 @@ import type {IProjectScope} from './IProjectScope';
 export interface IProjectServicesProvider extends IAsyncDisposable
 {
 	disposeService(service: DotNet.DotNetObject) : Promise<void>;
-	tryGetCrdtProjectName(code: string) : Promise<string>;
+	tryGetCrdtProjectName(code: string) : Promise<string | undefined>;
 	openCrdtProject(code: string) : Promise<IProjectScope>;
 	openFwDataProject(projectName: string) : Promise<IProjectScope>;
 }

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/ISyncServiceJsInvokable.ts

@@ -13,9 +13,9 @@ export interface ISyncServiceJsInvokable
 {
 	getSyncStatus() : Promise<IProjectSyncStatus>;
 	triggerFwHeadlessSync() : Promise<ISyncJobResult>;
-	countPendingCrdtCommits() : Promise<IPendingCommits>;
-	getLatestSyncedCommitDate() : Promise<string>;
+	countPendingCrdtCommits() : Promise<IPendingCommits | undefined>;
+	getLatestSyncedCommitDate() : Promise<string | undefined>;
 	executeSync(skipNotifications: boolean) : Promise<ISyncResults>;
-	getCurrentServer() : Promise<ILexboxServer>;
+	getCurrentServer() : Promise<ILexboxServer | undefined>;
 }
 /* eslint-enable */

frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IUpdateService.ts

@@ -3,12 +3,12 @@
 //     Changes to this file may cause incorrect behavior and will be lost if
 //     the code is regenerated.
 
-import type {UpdateResult} from '../AppUpdate/UpdateResult';
 import type {IAvailableUpdate} from '../AppUpdate/IAvailableUpdate';
+import type {UpdateResult} from '../AppUpdate/UpdateResult';
 
 export interface IUpdateService
 {
-	checkForUpdates() : Promise<IAvailableUpdate | null>;
+	checkForUpdates() : Promise<IAvailableUpdate | undefined>;
 	applyUpdate(update: IAvailableUpdate) : Promise<UpdateResult>;
 }
 /* eslint-enable */

frontend/viewer/src/lib/services/browser-app-services.ts

@@ -4,8 +4,8 @@ import type {IJsEventListener} from '$lib/dotnet-types/generated-types/FwLiteSha
 import type {IPreferencesService} from '$lib/dotnet-types/generated-types/FwLiteShared/Services/IPreferencesService';
 
 const localStoragePreferencesService: IPreferencesService = {
-  get(key: string): Promise<string | null> {
-    return Promise.resolve(localStorage.getItem(key));
+  get(key: string): Promise<string | undefined> {
+    return Promise.resolve(localStorage.getItem(key) ?? undefined);
   },
   set(key: string, value: string): Promise<void> {
     localStorage.setItem(key, value);
@@ -22,8 +22,8 @@ const noopJsEventListener: IJsEventListener = {
     // Never resolves — no events to deliver in a browser-only context
     return new Promise<IFwEvent>(() => {});
   },
-  lastEvent(): Promise<IFwEvent | null> {
-    return Promise.resolve(null);
+  lastEvent(): Promise<IFwEvent | undefined> {
+    return Promise.resolve(undefined);
   },
 };
 

frontend/viewer/src/lib/services/event-bus.ts

@@ -36,7 +36,7 @@ export class EventBus {
   }
 
   private async eventLoop(jsEventListener: IJsEventListener) {
-    let event: IFwEvent;
+    let event: IFwEvent | undefined;
     while (true) {
       event = await jsEventListener.nextEventAsync();
       if (!event) return;

frontend/viewer/src/lib/services/service-provider-dotnet.ts

@@ -66,7 +66,8 @@ export function wrapInProxy<K extends ServiceKey>(dotnetObject: DotNet.DotNetObj
         console.debug(`[Dotnet Proxy] Calling ${serviceName} method ${dotnetMethodName}`, args);
         args = transformArgs(args);
         try {
-          const result = await target.invokeMethodAsync(dotnetMethodName, ...args);
+          let result = await target.invokeMethodAsync(dotnetMethodName, ...args);
+          if (result === null) result = undefined;//ensure that if the return is null rewrite it to undefined to match the contract
           console.debug(`[Dotnet Proxy] ${serviceName} method ${dotnetMethodName} returned`, result);
           return result;
         } catch (error) {

frontend/viewer/src/lib/updates/UpdateDialog.svelte

@@ -16,7 +16,7 @@
   const config = useFwLiteConfig();
   const updateService = useUpdateService();
 
-  let checkPromise = $state<Promise<IAvailableUpdate | null>>();
+  let checkPromise = $state<Promise<IAvailableUpdate | undefined>>();
   let installPromise = $state<Promise<UpdateResult>>();
 
   const eventBus = useEventBus();

frontend/viewer/src/lib/updates/UpdateDialogContent.svelte

@@ -7,7 +7,7 @@
   import {getReleaseUrl} from './utils';
 
   type Props = {
-    checkPromise?: Promise<IAvailableUpdate | null>;
+    checkPromise?: Promise<IAvailableUpdate | undefined>;
     installPromise?: Promise<UpdateResult>;
     installUpdate: (update: IAvailableUpdate) => Promise<void>;
     installProgress?: number;

frontend/viewer/src/project/browse/EntryView.svelte

@@ -66,7 +66,7 @@
     },
   );
 
-  function snapshotEntry(entry: IEntry | null): IEntry | null {
+  function snapshotEntry(entry: IEntry | undefined): IEntry | undefined {
     // IMMEDIATELY take a snapshot to ensure it doesn't get mutated by the editor before EntryPersistence gets it.
     // (dirty fields immediately push their current dirty value into the entry object, which can corrupt the update diff.)
     latestPersistedSnapshot = entry ? Object.freeze(copy(entry)) : undefined;
@@ -76,7 +76,7 @@
 
   // For entry updates that arrive OUTSIDE the resource fetcher (event bus, restore), we must
   // push the new value into the resource ourselves via mutate().
-  function setEntry(entry: IEntry | null): IEntry | null {
+  function setEntry(entry: IEntry | undefined): IEntry | undefined {
     snapshotEntry(entry);
     entryResource.mutate(entry);
     return entry;