add typings for createEventDispatcher (#5260)

sveltejs · Aug 12, 2020 · aa7e5e3 · aa7e5e3
1 parent 6ebe7f8
commit aa7e5e3
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/src/runtime/internal/lifecycle.ts b/src/runtime/internal/lifecycle.ts
@@ -27,7 +27,9 @@ export function onDestroy(fn) {
  get_current_component().$$.on_destroy.push(fn);
 }
 
-export function createEventDispatcher() {
+export function createEventDispatcher<
+ EventMap extends {} = any
+>(): <EventKey extends Extract<keyof EventMap, string>>(type: EventKey, detail?: EventMap[EventKey]) => void {
  const component = get_current_component();
 
  return (type: string, detail?: any) => {
@@ -61,4 +63,4 @@ export function bubble(component, event) {
  if (callbacks) {
  callbacks.slice().forEach(fn => fn(event));
  }
-}
+}