Merge pull request #52 from Dashlane/fix/create-event-bus-return-type

Fix/createEventBus return type

jest.config.ts

@@ -0,0 +1,15 @@
+import type { InitialOptionsTsJest } from "ts-jest/dist/types";
+
+const config: InitialOptionsTsJest = {
+    globals: {
+        "ts-jest": {
+            tsconfig: "tsconfig.json",
+        },
+    },
+    moduleFileExtensions: ["ts", "js"],
+    preset: "ts-jest",
+    rootDir: "test",
+    testMatch: ["**/*.spec.ts"],
+    verbose: true,
+};
+export default config;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-event-bus",
-  "version": "4.1.0",
+  "version": "4.1.1",
   "description": "Distributed messaging in Typescript",
   "main": "build/index.js",
   "typings": "build/index.d.ts",
@@ -45,9 +45,12 @@
     "@types/chrome": "^0.0.155",
     "@types/jest": "^26.0.20",
     "@types/ws": "^3.2.1",
+    "expect-type": "^0.13.0",
     "husky": "^4.3.8",
-    "jest": "^26.6.3",
+    "jest": "^28.1.3",
     "npm-run-all": "^4.1.5",
+    "ts-jest": "^28.0.7",
+    "ts-node": "^10.9.1",
     "tslint": "^5.6.0",
     "typescript": "~4.1.3",
     "typescript-formatter": "^7.2.2",

src/Events.ts

@@ -36,12 +36,12 @@ export function combineEvents<
 
 export function createEventBus<
     C extends EventDeclaration,
-    T extends Array<keyof C>
+    T extends Array<keyof C> = []
 >(args: {
     events: C;
     channels?: Channel[];
     ignoredEvents?: T;
-}): Omit<C, T[number]> {
+}): T extends [] ? C : Omit<C, T[number]> {
 
     const transports = (args.channels || []).map(
         (c) => new Transport(c, (args.ignoredEvents as string[]))
@@ -62,5 +62,6 @@ export function createEventBus<
         }
     }
 
-    return eventBus as Omit<C, T[number]>
+    return eventBus as T extends [] ? C : Omit<C, T[number]>
 }
+

test/Event.spec.ts

@@ -1,5 +1,5 @@
 import { slot } from './../src/Slot'
-import { combineEvents, createEventBus, omitEvents } from './../src/Events'
+import { combineEvents, createEventBus } from './../src/Events'
 import { TestChannel } from './TestChannel'
 import { DEFAULT_PARAM } from './../src/Constants'
 

test/Types.spec.ts

@@ -0,0 +1,32 @@
+import { expectTypeOf } from 'expect-type'
+import { createEventBus } from '../src/Events'
+import { Slot, slot } from '../src/Slot'
+
+describe('createEventBus', () => {
+    type Events = {
+        numberToString: Slot<number, string>
+        eventToIgnore: Slot<void, void>
+    }
+
+    type FilteredEvents = {
+        numberToString: Slot<number, string>
+    }
+
+    const events: Events = {
+        numberToString: slot<number, string>(),
+        eventToIgnore: slot<void, void>(),
+    }
+
+    it('should return the right types regardless of an ingnoredEvents list being passed or not', () => {
+        const eventBus = createEventBus({ events })
+        const eventBusWithIgnored = createEventBus({
+            events,
+            ignoredEvents: ['eventToIgnore'],
+        })
+
+        expectTypeOf(eventBus).toEqualTypeOf<Events>()
+        expectTypeOf(eventBus).not.toEqualTypeOf<FilteredEvents>()
+        expectTypeOf(eventBusWithIgnored).not.toEqualTypeOf<Events>()
+        expectTypeOf(eventBusWithIgnored).toEqualTypeOf<FilteredEvents>()
+    })
+})