fix: ensure types of all form actions are accessible (#8877)

* fix: ensure types of all form actions are accessible

fixes #8865

* THAS HAS

.changeset/breezy-cycles-thank.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: ensure types of all form actions are accessible even if differing

packages/kit/test/types/actions.test.ts

@@ -11,3 +11,15 @@ form.message = '';
 form.success = true;
 // @ts-expect-error - cannot both be present at the same time
 form = { message: '', success: true };
+
+// Test: Actions with different return types are transformed into a union that has all types accessible
+type Actions2 = {
+	foo: () => Promise<{ message: string }>;
+	bar: () => Promise<{ success: boolean }>;
+};
+
+let form2: Kit.AwaitedActions<Actions2> = null as any;
+form2.message = '';
+form2.success = true;
+// @ts-expect-error - cannot both be present at the same time
+form2 = { message: '', success: true };

packages/kit/types/index.d.ts

@@ -50,9 +50,11 @@ export type AwaitedProperties<input extends Record<string, any> | void> =
 		? OptionalUnion<AwaitedPropertiesUnion<input>>
 		: AwaitedPropertiesUnion<input>;
 
-export type AwaitedActions<T extends Record<string, (...args: any) => any>> = {
-	[Key in keyof T]: OptionalUnion<UnpackValidationError<Awaited<ReturnType<T[Key]>>>>;
-}[keyof T];
+export type AwaitedActions<T extends Record<string, (...args: any) => any>> = OptionalUnion<
+	{
+		[Key in keyof T]: UnpackValidationError<Awaited<ReturnType<T[Key]>>>;
+	}[keyof T]
+>;
 
 // Takes a union type and returns a union type where each type also has all properties
 // of all possible types (typed as undefined), making accessing them more ergonomic