From 6040e1cceb2f002868e2f7f74dba54aba45ece1c Mon Sep 17 00:00:00 2001
From: Curt Grimes <curt@curtgrimes.com>
Date: Thu, 9 Nov 2023 08:54:53 -0600
Subject: [PATCH] feat(createEventHook): allow trigger to optionally have no
 parameters (#3507)

---
 packages/shared/createEventHook/index.test.ts | 12 ++++++++++++
 packages/shared/createEventHook/index.ts      | 17 +++++++++--------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/packages/shared/createEventHook/index.test.ts b/packages/shared/createEventHook/index.test.ts
index ec7ccc86e5b..366164ec620 100644
--- a/packages/shared/createEventHook/index.test.ts
+++ b/packages/shared/createEventHook/index.test.ts
@@ -27,6 +27,18 @@ describe('createEventHook', () => {
     expect(message).toBe('Hello World')
   })
 
+  it('should trigger event with no params', () => {
+    let timesFired = 0
+
+    const { on: onResult, trigger } = createEventHook()
+
+    onResult(() => timesFired++)
+    trigger()
+    trigger()
+
+    expect(timesFired).toBe(2)
+  })
+
   it('should add and remove event listener', () => {
     const listener = vi.fn()
     const { on, off, trigger } = createEventHook<string>()
diff --git a/packages/shared/createEventHook/index.ts b/packages/shared/createEventHook/index.ts
index d9a4f535227..9f99ee7d339 100644
--- a/packages/shared/createEventHook/index.ts
+++ b/packages/shared/createEventHook/index.ts
@@ -4,9 +4,10 @@
  */
 import { tryOnScopeDispose } from '../tryOnScopeDispose'
 
-export type EventHookOn<T = any> = (fn: (param: T) => void) => { off: () => void }
-export type EventHookOff<T = any> = (fn: (param: T) => void) => void
-export type EventHookTrigger<T = any> = (param: T) => Promise<unknown[]>
+type Callback<T> = T extends void ? () => void : (param: T) => void
+export type EventHookOn<T = any> = (fn: Callback<T>) => { off: () => void }
+export type EventHookOff<T = any> = (fn: Callback<T>) => void
+export type EventHookTrigger<T = any> = (param?: T) => Promise<unknown[]>
 
 export interface EventHook<T = any> {
   on: EventHookOn<T>
@@ -20,13 +21,13 @@ export interface EventHook<T = any> {
  * @see https://vueuse.org/createEventHook
  */
 export function createEventHook<T = any>(): EventHook<T> {
-  const fns: Set<(param: T) => void> = new Set()
+  const fns: Set<Callback<T>> = new Set()
 
-  const off = (fn: (param: T) => void) => {
+  const off = (fn: Callback<T>) => {
     fns.delete(fn)
   }
 
-  const on = (fn: (param: T) => void) => {
+  const on = (fn: Callback<T>) => {
     fns.add(fn)
     const offFn = () => off(fn)
 
@@ -37,8 +38,8 @@ export function createEventHook<T = any>(): EventHook<T> {
     }
   }
 
-  const trigger = (param: T) => {
-    return Promise.all(Array.from(fns).map(fn => fn(param)))
+  const trigger: EventHookTrigger<T> = (param?: T) => {
+    return Promise.all(Array.from(fns).map(fn => param ? fn(param) : (fn as Callback<void>)()))
   }
 
   return {