feat(createEventHook): added interface (#531)

* feat(createEventHook): added interface

* added types for EventHookOn, EventHookOff, and EventHook trigger

packages/core/useFetch/index.ts

@@ -1,5 +1,5 @@
 import { Ref, ref, unref, watch, computed, ComputedRef, shallowRef } from 'vue-demi'
-import { Fn, MaybeRef, containsProp, createEventHook } from '@vueuse/shared'
+import { Fn, MaybeRef, containsProp, createEventHook, EventHookOn } from '@vueuse/shared'
 import { defaultWindow } from '../_configurable'
 
 interface UseFetchReturnBase<T> {
@@ -56,12 +56,12 @@ interface UseFetchReturnBase<T> {
   /**
    * Fires after the fetch request has finished
    */
-  onFetchResponse: (fn: (response: Response) => void) => { off: () => void }
+  onFetchResponse: EventHookOn<Response>
 
   /**
    * Fires after a fetch request error
    */
-  onFetchError: (fn: (error: any) => void) => { off: () => void }
+  onFetchError: EventHookOn
 }
 
 type DataType = 'text' | 'json' | 'blob' | 'arrayBuffer' | 'formData'

packages/shared/createEventHook/index.ts

@@ -1,14 +1,24 @@
 /**
- * The source code for this function was inspiried by vue-apollo's `useEventHook` util
+ * The source code for this function was inspired by vue-apollo's `useEventHook` util
  * https://github.com/vuejs/vue-apollo/blob/v4/packages/vue-apollo-composable/src/util/useEventHook.ts
  */
 
+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) => void
+
+export interface EventHook<T = any> {
+  on: EventHookOn<T>
+  off: EventHookOff<T>
+  trigger: EventHookTrigger<T>
+}
+
 /**
  * Utility for creating event hooks
  *
  * @see https://vueuse.org/createEventHook
  */
-export function createEventHook<T = any>() {
+export function createEventHook<T = any>(): EventHook<T> {
   const fns: Array<(param: T) => void> = []
 
   const off = (fn: (param: T) => void) => {