Fixed an issue with typegen types not being able to provide events th…

…at had a union of strings as their `type` (#3230)

* Fixed an issue with typegen types not being able to provide events that had a union of strings as their `type`

* Remove `typesVersions` attempt from the core

.changeset/fast-ways-run.md

@@ -0,0 +1,5 @@
+---
+'xstate': patch
+---
+
+Fixed an issue with typegen types not being able to provide events that had a union of strings as their `type` (such as `{ type: 'INC' | 'DEC'; value: number; }`).

packages/core/src/types.ts

@@ -20,9 +20,12 @@ export type Compute<A extends any> = { [K in keyof A]: A[K] } & unknown;
 export type Prop<T, K> = K extends keyof T ? T[K] : never;
 export type Values<T> = T[keyof T];
 export type Merge<M, N> = Omit<M, keyof N> & N;
+// TODO: replace in v5 with:
+// export type IndexByType<T extends { type: string }> = { [E in T as E['type']]: E; };
 export type IndexByType<T extends { type: string }> = {
-  [K in T['type']]: Extract<T, { type: K }>;
+  [K in T['type']]: T extends any ? (K extends T['type'] ? T : never) : never;
 };
+
 export type Equals<A1 extends any, A2 extends any> = (<A>() => A extends A2
   ? true
   : false) extends <A>() => A extends A1 ? true : false

packages/core/test/typegenTypes.test.ts

@@ -1260,4 +1260,34 @@ describe('typegen types', () => {
       }
     );
   });
+
+  it('should be able to provide events that use string unions as their type', () => {
+    interface TypesMeta extends TypegenMeta {
+      eventsCausingActions: {
+        increment: 'INC';
+        decrement: 'DEC';
+      };
+    }
+
+    createMachine(
+      {
+        tsTypes: {} as TypesMeta,
+        schema: {
+          context: {} as {
+            count: number;
+          },
+          events: {} as { type: 'INC' | 'DEC'; value: number }
+        }
+      },
+      {
+        actions: {
+          increment: assign((ctx, ev) => {
+            return {
+              count: ctx.count + ev.value
+            };
+          })
+        }
+      }
+    );
+  });
 });