enhance(api): add generic parameter to emit and emitTo functions (#13066)

closes #13059

.changes/change-pr-13066.md

@@ -0,0 +1,4 @@
+---
+"@tauri-apps/api": patch:enhance
+---
+Add a generic to `emit` and `emitTo` functions for the `payload` instead of the previously used type (`unknown`).

packages/api/src/event.ts

@@ -174,7 +174,7 @@ async function once<T>(
  *
  * @since 1.0.0
  */
-async function emit(event: string, payload?: unknown): Promise<void> {
+async function emit<T>(event: string, payload?: T): Promise<void> {
   await invoke('plugin:event|emit', {
     event,
     payload
@@ -196,10 +196,10 @@ async function emit(event: string, payload?: unknown): Promise<void> {
  *
  * @since 2.0.0
  */
-async function emitTo(
+async function emitTo<T>(
   target: EventTarget | string,
   event: string,
-  payload?: unknown
+  payload?: T
 ): Promise<void> {
   const eventTarget: EventTarget =
     typeof target === 'string' ? { kind: 'AnyLabel', label: target } : target

packages/api/src/webview.ts

@@ -291,7 +291,7 @@ class Webview {
    * @param event Event name. Must include only alphanumeric characters, `-`, `/`, `:` and `_`.
    * @param payload Event payload.
    */
-  async emit(event: string, payload?: unknown): Promise<void> {
+  async emit<T>(event: string, payload?: T): Promise<void> {
     if (localTauriEvents.includes(event)) {
       // eslint-disable-next-line
       for (const handler of this.listeners[event] || []) {
@@ -303,7 +303,7 @@ class Webview {
       }
       return
     }
-    return emit(event, payload)
+    return emit<T>(event, payload)
   }
 
   /**
@@ -319,10 +319,10 @@ class Webview {
    * @param event Event name. Must include only alphanumeric characters, `-`, `/`, `:` and `_`.
    * @param payload Event payload.
    */
-  async emitTo(
+  async emitTo<T>(
     target: string | EventTarget,
     event: string,
-    payload?: unknown
+    payload?: T
   ): Promise<void> {
     if (localTauriEvents.includes(event)) {
       // eslint-disable-next-line
@@ -335,7 +335,7 @@ class Webview {
       }
       return
     }
-    return emitTo(target, event, payload)
+    return emitTo<T>(target, event, payload)
   }
 
   /** @ignore */

packages/api/src/window.ts

@@ -441,7 +441,7 @@ class Window {
    * @param event Event name. Must include only alphanumeric characters, `-`, `/`, `:` and `_`.
    * @param payload Event payload.
    */
-  async emit(event: string, payload?: unknown): Promise<void> {
+  async emit<T>(event: string, payload?: T): Promise<void> {
     if (localTauriEvents.includes(event)) {
       // eslint-disable-next-line
       for (const handler of this.listeners[event] || []) {
@@ -453,7 +453,7 @@ class Window {
       }
       return
     }
-    return emit(event, payload)
+    return emit<T>(event, payload)
   }
 
   /**
@@ -468,10 +468,10 @@ class Window {
    * @param event Event name. Must include only alphanumeric characters, `-`, `/`, `:` and `_`.
    * @param payload Event payload.
    */
-  async emitTo(
+  async emitTo<T>(
     target: string | EventTarget,
     event: string,
-    payload?: unknown
+    payload?: T
   ): Promise<void> {
     if (localTauriEvents.includes(event)) {
       // eslint-disable-next-line security/detect-object-injection
@@ -484,7 +484,7 @@ class Window {
       }
       return
     }
-    return emitTo(target, event, payload)
+    return emitTo<T>(target, event, payload)
   }
 
   /** @ignore */