From ce708fbba8fd41f8dd45fff0568657f8001caabc Mon Sep 17 00:00:00 2001
From: Matt Pharoah <mtpharoah@gmail.com>
Date: Wed, 8 Feb 2023 17:01:00 -0500
Subject: [PATCH] Perform type checking of the event detail in the emit
 function if the event type matches a Shoelace event

---
 src/internal/shoelace-element.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/internal/shoelace-element.ts b/src/internal/shoelace-element.ts
index 2188e9e9..7534098a 100644
--- a/src/internal/shoelace-element.ts
+++ b/src/internal/shoelace-element.ts
@@ -1,13 +1,19 @@
 import { LitElement } from 'lit';
 import { property } from 'lit/decorators.js';
 
+type SlEventInit<T> = T extends keyof GlobalEventHandlersEventMap
+  ? GlobalEventHandlersEventMap[T] extends CustomEvent
+    ? CustomEventInit<GlobalEventHandlersEventMap[T]['detail']>
+    : CustomEventInit
+  : CustomEventInit;
+
 export default class ShoelaceElement extends LitElement {
   // Make localization attributes reactive
   @property() dir: string;
   @property() lang: string;
 
   /** Emits a custom event with more convenient defaults. */
-  emit(name: string, options?: CustomEventInit) {
+  emit<T extends string>(name: T, options?: SlEventInit<T>) {
     const event = new CustomEvent(name, {
       bubbles: true,
       cancelable: false,