Fix typing for callback services

.changeset/plenty-bobcats-battle.md

@@ -0,0 +1,5 @@
+---
+'xstate-codegen': patch
+---
+
+Fix type definition for callback services

packages/xstate-compiled/examples/callbackServiceMachine.machine.ts

@@ -0,0 +1,49 @@
+import { Machine, interpret } from '@xstate/compiled';
+
+interface Context {}
+
+type Event =
+  | { type: 'INIT', data: string }
+  | { type: 'LOG' }
+
+const machine = Machine<Context, Event, 'callbackServiceMachine'>({
+  initial: 'idle',
+  states: {
+    idle: {
+      on: {
+        INIT: 'active'
+      }
+    },
+    active: {
+      invoke: [
+        {
+          src: 'listen',
+        },
+      ],
+      on: {
+        LOG: {
+          actions: 'logAction'
+        }
+      }
+    },
+  },
+});
+
+interpret(
+  machine.withConfig({
+    services: {
+      listen: (_context, _event) => (send, onReceive) => {
+        send({ type: 'LOG' })
+
+        onReceive(e => {
+          if (e.type === 'LOG') {
+            console.log('log here too')
+          }
+        })
+      }
+    },
+    actions: {
+      logAction: (_context, _event) => console.log('received event')
+    },
+  }),
+);

packages/xstate-compiled/examples/package.json

@@ -5,10 +5,10 @@
   "license": "MIT",
   "repository": "https://github.com/mattpocock/xstate-codegen",
   "dependencies": {
-    "xstate": "^4.12.0",
     "@xstate/react": "0.8.1",
     "react": "16.13.1",
-    "typescript": "3.9.7"
+    "typescript": "3.9.7",
+    "xstate": "^4.12.0"
   },
   "scripts": {
     "build": "tsc"

packages/xstate-compiled/src/templates/index.d.ts.hbs

@@ -1,4 +1,5 @@
 import {
+  AnyEventObject,
   EventObject,
   SingleOrArray,
   InvokeConfig,
@@ -21,7 +22,11 @@ import {
   assign,
   send,
   Expr,
+  Subscribable,
+  Sender,
+  Receiver,
   InterpreterOptions,
+  InvokeMeta,
 } from 'xstate';
 import {
   StateWithMatches,
@@ -36,6 +41,25 @@ import { StateNode } from 'xstate/lib/StateNode';
 declare module '@xstate/compiled' {
   type TwoLevelPartial<T extends object> = { [K in keyof T]?: Partial<T[K]>};
 
+  type InvokeCallback<
+    TEvent extends EventObject,
+    TSentEvent extends EventObject
+  > = (
+    callback: Sender<TSentEvent>,
+    onReceive: Receiver<TEvent>
+  ) => (() => void) | Promise<any> | void;
+
+  type NarrowedInvokeCreator<TContext, 
+    TEvent extends EventObject, 
+    TInitEvent extends EventObject, 
+    TFinalContext = any
+  > = 
+    (context: TContext, event: TInitEvent, meta: InvokeMeta) => 
+      | PromiseLike<TFinalContext> 
+      | StateMachine<TFinalContext, any, any> 
+      | Subscribable<EventObject> 
+      | InvokeCallback<any, TEvent>;
+
   /** Generated Types */
   {{#each machines}}
   export class {{capitalize this.id}}StateMachine<
@@ -114,8 +138,9 @@ declare module '@xstate/compiled' {
       {{#if this.machine.services}}
       services{{#unless this.machine.services.required}}?{{/unless}}: {
         {{#each this.machine.services.lines}}
-        {{this.name}}{{#unless this.required}}?{{/unless}}: InvokeCreator<
+        {{this.name}}{{#unless this.required}}?{{/unless}}: NarrowedInvokeCreator<
           TContext, 
+          TEvent,
           {{#if this.events}}
           Extract<TEvent,
           {{#each this.events}}