Add tests

package.json

@@ -17,9 +17,9 @@
   ],
   "devDependencies": {
     "@changesets/cli": "^2.26.0",
-    "node-qunit-puppeteer": "^2.2.0",
     "bundlesize": "^1.0.0-beta.2",
     "local-web-server": "^4.2.1",
+    "node-qunit-puppeteer": "^2.2.0",
     "wireit": "^0.9.3"
   },
   "wireit": {
@@ -31,5 +31,8 @@
         }
       }
     }
+  },
+  "dependencies": {
+    "expect-type": "^1.1.0"
   }
 }

packages/core/package.json

@@ -29,6 +29,8 @@
     "bundlesize": "wireit",
     "server": "wireit",
     "test": "wireit",
+    "test:types": "wireit",
+    "test:browser": "wireit",
     "build:cjs": "wireit",
     "build": "wireit"
   },
@@ -74,6 +76,16 @@
       }
     },
     "test": {
+      "dependencies": [
+        "test:types",
+        "test:browser"
+      ]
+    },
+    "test:types": {
+      "command": "tsc -p test/types/tsconfig.json",
+      "files": []
+    },
+    "test:browser": {
       "command": "node-qunit-puppeteer http://localhost:1965/test/test.html 10000",
       "dependencies": [
         "server"

packages/core/test/types/send.ts

@@ -0,0 +1,24 @@
+import { expectTypeOf } from 'expect-type';
+import { test } from 'node:test';
+import {
+  type Service,
+  createMachine,
+  transition,
+  state,
+} from 'robot3';
+
+test('send(event) is typed', () => {
+  const machine = createMachine({
+    one: state(transition('go-two', 'two')),
+    two: state(transition('go-one', 'one')),
+    three: state()
+  });
+
+  type Params = Parameters<Service<typeof machine>['send']>;
+  type EventParam = Params[0];
+  type StringParams = Extract<EventParam, string>;
+  expectTypeOf<StringParams>().toEqualTypeOf<'go-one' | 'go-two'>();
+
+  type ObjectParams = Extract<EventParam, { type: string; }>;
+  expectTypeOf<ObjectParams['type']>().toEqualTypeOf<'go-one' | 'go-two'>();
+});

packages/core/test/types/tsconfig.json

@@ -0,0 +1,33 @@
+{
+  "include": ["../..", "."],
+  "exclude": ["../../node_modules"],
+  "compilerOptions": {
+    /* Base Options: */
+    "esModuleInterop": true,
+    "skipLibCheck": false,
+    "target": "es2022",
+    "allowJs": false,
+    "moduleDetection": "force",
+    "isolatedModules": true,
+    "moduleResolution": "nodenext",
+
+    /* Strictness */
+    "strict": true,
+    "noUncheckedIndexedAccess": true,
+    "noImplicitOverride": true,
+
+    /* AND if you're building for a library: */
+    "declaration": true,
+
+    /* AND if you're building for a library in a monorepo: */
+    "composite": true,
+    "declarationMap": true,
+
+    /* If NOT transpiling with TypeScript: */
+    "module": "nodenext",
+    "noEmit": true,
+
+    /* If your code runs in the DOM: */
+    "lib": ["es2022", "dom", "dom.iterable"]
+  }
+}