add types tests

package.json

@@ -83,8 +83,9 @@
   },
   "types": "types/runtime/index.d.ts",
   "scripts": {
-    "test": "mocha --exit",
+    "test": "mocha --exit && npm run test:types",
     "test:unit": "mocha --require sucrase/register --recursive src/**/__test__.ts --exit",
+    "test:types": "tsc --project test/types/tsconfig.json --noEmit",
     "quicktest": "mocha",
     "build": "rollup -c && npm run tsd",
     "prepare": "npm run build",

test/types/runtime/internal/lifecyle.test-types.ts

@@ -0,0 +1,33 @@
+import { createEventDispatcher } from '$runtime/internal/lifecycle';
+
+const dispatch = createEventDispatcher<{
+   loaded: never
+   change: string
+   valid: boolean
+   optional: number | null
+}>();
+
+// @ts-expect-error: dispatch invalid event
+dispatch('some-event');
+
+dispatch('loaded');
+// @ts-expect-error: no detail accepted
+dispatch('loaded', 123);
+
+// @ts-expect-error: detail not provided
+dispatch('change');
+dispatch('change', 'string');
+// @ts-expect-error: wrong type of detail
+dispatch('change', 123);
+// @ts-expect-error: wrong type of detail
+dispatch('change', undefined);
+
+dispatch('valid', true);
+// @ts-expect-error: wrong type of detail
+dispatch('valid', 'string');
+
+dispatch('optional');
+dispatch('optional', 123);
+dispatch('optional', null);
+// @ts-expect-error: wrong type of optional detail
+dispatch('optional', 'string');

test/types/tsconfig.json

@@ -0,0 +1,28 @@
+{
+	"compilerOptions": {
+		"moduleResolution": "node",
+		"module": "ESNext",
+		"lib": ["ESNext", "DOM"],
+		"target": "ESNext",
+		"isolatedModules": true,
+		"resolveJsonModule": true,
+		"esModuleInterop": true,
+		"skipLibCheck": true,
+		"forceConsistentCasingInFileNames": true,
+		"baseUrl": "../../",
+		"allowJs": true,
+		"checkJs": true,
+		"paths": {
+			"$runtime/*": ["src/runtime/*"]
+		},
+		// enable strictest options
+		"allowUnreachableCode": false,
+		"alwaysStrict": true,
+		"noFallthroughCasesInSwitch": true,
+		"noImplicitAny": true,
+		"noImplicitReturns": true,
+		"noImplicitThis": true,
+		"strict": true,
+	},
+	"include": ["**/*.test-types.ts"]
+}