feat: type `currentTarget` in `on` function (#17370)

* feat: type `currentTarget` in `on` function

* `EventTarget &` is redundant, `Element` already extends `EventTarget`

* no need for optional chaining

* add currentTarget for other overloads

* update changeset

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>

.changeset/bumpy-radios-live.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: type `currentTarget` in `on` function

packages/svelte/src/events/public.d.ts

@@ -8,7 +8,7 @@
 export function on<Type extends keyof WindowEventMap>(
 	window: Window,
 	type: Type,
-	handler: (this: Window, event: WindowEventMap[Type]) => any,
+	handler: (this: Window, event: WindowEventMap[Type] & { currentTarget: Window }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**
@@ -19,7 +19,7 @@ export function on<Type extends keyof WindowEventMap>(
 export function on<Type extends keyof DocumentEventMap>(
 	document: Document,
 	type: Type,
-	handler: (this: Document, event: DocumentEventMap[Type]) => any,
+	handler: (this: Document, event: DocumentEventMap[Type] & { currentTarget: Document }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**
@@ -30,7 +30,7 @@ export function on<Type extends keyof DocumentEventMap>(
 export function on<Element extends HTMLElement, Type extends keyof HTMLElementEventMap>(
 	element: Element,
 	type: Type,
-	handler: (this: Element, event: HTMLElementEventMap[Type]) => any,
+	handler: (this: Element, event: HTMLElementEventMap[Type] & { currentTarget: Element }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**
@@ -41,7 +41,7 @@ export function on<Element extends HTMLElement, Type extends keyof HTMLElementEv
 export function on<Element extends MediaQueryList, Type extends keyof MediaQueryListEventMap>(
 	element: Element,
 	type: Type,
-	handler: (this: Element, event: MediaQueryListEventMap[Type]) => any,
+	handler: (this: Element, event: MediaQueryListEventMap[Type] & { currentTarget: Element }) => any,
 	options?: AddEventListenerOptions | undefined
 ): () => void;
 /**

packages/svelte/tests/types/events.ts

@@ -8,6 +8,8 @@ on(window, 'click', (e) => e.button);
 
 on(document, 'click', (e) => e.button);
 
+on(document.createElement('input'), 'input', (e) => e.currentTarget.value);
+
 on(
 	document.body,
 	'clidck',

packages/svelte/types/index.d.ts

@@ -2810,7 +2810,7 @@ declare module 'svelte/events' {
 	export function on<Type extends keyof WindowEventMap>(
 		window: Window,
 		type: Type,
-		handler: (this: Window, event: WindowEventMap[Type]) => any,
+		handler: (this: Window, event: WindowEventMap[Type] & { currentTarget: Window }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**
@@ -2821,7 +2821,7 @@ declare module 'svelte/events' {
 	export function on<Type extends keyof DocumentEventMap>(
 		document: Document,
 		type: Type,
-		handler: (this: Document, event: DocumentEventMap[Type]) => any,
+		handler: (this: Document, event: DocumentEventMap[Type] & { currentTarget: Document }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**
@@ -2832,7 +2832,7 @@ declare module 'svelte/events' {
 	export function on<Element extends HTMLElement, Type extends keyof HTMLElementEventMap>(
 		element: Element,
 		type: Type,
-		handler: (this: Element, event: HTMLElementEventMap[Type]) => any,
+		handler: (this: Element, event: HTMLElementEventMap[Type] & { currentTarget: Element }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**
@@ -2843,7 +2843,7 @@ declare module 'svelte/events' {
 	export function on<Element extends MediaQueryList, Type extends keyof MediaQueryListEventMap>(
 		element: Element,
 		type: Type,
-		handler: (this: Element, event: MediaQueryListEventMap[Type]) => any,
+		handler: (this: Element, event: MediaQueryListEventMap[Type] & { currentTarget: Element }) => any,
 		options?: AddEventListenerOptions | undefined
 	): () => void;
 	/**