Allow toService to be bound to async service

src/container/container.ts

@@ -331,6 +331,12 @@ class Container implements interfaces.Container {
     return this._get<T>(getArgs) as Promise<T> | T;
   }
 
+  public getMaybeAsync<T>(serviceIdentifier: interfaces.ServiceIdentifier<T>): Promise<T> | T {
+    const getArgs = this._getNotAllArgs(serviceIdentifier, false);
+
+    return this._get<T>(getArgs) as Promise<T> | T;
+  }
+
   public getTagged<T>(serviceIdentifier: interfaces.ServiceIdentifier<T>, key: string | number | symbol, value: unknown): T {
     const getArgs = this._getNotAllArgs(serviceIdentifier, false, key, value);
 

src/interfaces/interfaces.ts

@@ -208,6 +208,7 @@ namespace interfaces {
     getAllTagged<T>(serviceIdentifier: ServiceIdentifier<T>, key: string | number | symbol, value: unknown): T[];
     getAllNamed<T>(serviceIdentifier: ServiceIdentifier<T>, named: string | number | symbol): T[];
     getAsync<T>(serviceIdentifier: ServiceIdentifier<T>): Promise<T>;
+    getMaybeAsync<T>(serviceIdentifier: ServiceIdentifier<T>): Promise<T> | T
     getNamedAsync<T>(serviceIdentifier: ServiceIdentifier<T>, named: string | number | symbol): Promise<T>;
     getTaggedAsync<T>(serviceIdentifier: ServiceIdentifier<T>, key: string | number | symbol, value: unknown): Promise<T>;
     getAllAsync<T>(serviceIdentifier: ServiceIdentifier<T>): Promise<T[]>;

src/syntax/binding_to_syntax.ts

@@ -93,7 +93,7 @@ class BindingToSyntax<T> implements interfaces.BindingToSyntax<T> {
 
   public toService(service: string | symbol | interfaces.Newable<T> | interfaces.Abstract<T>): void {
     this.toDynamicValue(
-      (context) => context.container.get<T>(service)
+      (context) => context.container.getMaybeAsync(service)
     );
   }
 

test/resolution/resolver.test.ts

@@ -2597,4 +2597,22 @@ describe("Resolve", () => {
     expect(serviceFromGetAsync).eql(asyncServiceDynamicResolvedValue);
     expect(serviceFromGet).eql(asyncServiceDynamicResolvedValue);
   });
+
+  it("Should resolve service with async @postConstruct()", async () => {
+    @injectable()
+    class B {
+      @postConstruct()
+      async init() {
+        //
+      }
+    }
+
+    const container = new Container()
+    container.bind(B).toSelf().inSingletonScope()
+    container.bind('X').toService(B)
+
+    const x = await container.getAsync('X');
+    const b = await container.getAsync(B);
+    expect(b).eql(x)
+  })
 });