From 19043f226882ac5054f338fe07783e0a3dccbc9b Mon Sep 17 00:00:00 2001
From: Alex Macleod <alex@macleod.io>
Date: Wed, 20 Oct 2021 18:10:27 +0100
Subject: [PATCH 1/3] Use MessageEvent in EventSource#addEventListener

Fixes #736
---
 baselines/dom.generated.d.ts           | 4 ++--
 baselines/serviceworker.generated.d.ts | 4 ++--
 baselines/sharedworker.generated.d.ts  | 4 ++--
 baselines/webworker.generated.d.ts     | 4 ++--
 src/build/emitter.ts                   | 7 ++++++-
 5 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index b705170a2..7bfb1e28a 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -4928,9 +4928,9 @@ interface EventSource extends EventTarget {
     readonly CONNECTING: number;
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/baselines/serviceworker.generated.d.ts b/baselines/serviceworker.generated.d.ts
index 21f97453d..0780ac4b8 100644
--- a/baselines/serviceworker.generated.d.ts
+++ b/baselines/serviceworker.generated.d.ts
@@ -1300,9 +1300,9 @@ interface EventSource extends EventTarget {
     readonly CONNECTING: number;
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/baselines/sharedworker.generated.d.ts b/baselines/sharedworker.generated.d.ts
index 23d312a72..c17c101bc 100644
--- a/baselines/sharedworker.generated.d.ts
+++ b/baselines/sharedworker.generated.d.ts
@@ -1244,9 +1244,9 @@ interface EventSource extends EventTarget {
     readonly CONNECTING: number;
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/baselines/webworker.generated.d.ts b/baselines/webworker.generated.d.ts
index 6d622b95f..d108ca24f 100644
--- a/baselines/webworker.generated.d.ts
+++ b/baselines/webworker.generated.d.ts
@@ -1338,9 +1338,9 @@ interface EventSource extends EventTarget {
     readonly CONNECTING: number;
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/src/build/emitter.ts b/src/build/emitter.ts
index 7a3e2d8e6..139db0399 100644
--- a/src/build/emitter.ts
+++ b/src/build/emitter.ts
@@ -1064,8 +1064,13 @@ export function emitWebIdl(
           : "EventListenerOptions";
       if (tryEmitTypedEventHandlerForInterface(addOrRemove, optionsType)) {
         // only emit the string event handler if we just emitted a typed handler
+        const listener =
+          i.name === "EventSource"
+            ? "(this: EventSource, event: MessageEvent) => any"
+            : "EventListenerOrEventListenerObject";
+
         printer.printLine(
-          `${fPrefix}${addOrRemove}EventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | ${optionsType}): void;`
+          `${fPrefix}${addOrRemove}EventListener(type: string, listener: ${listener}, options?: boolean | ${optionsType}): void;`
         );
       }
     }

From 7d24773bbe4eb8d0d5e929234cc46b8221cb5a89 Mon Sep 17 00:00:00 2001
From: Alex Macleod <alex@macleod.io>
Date: Sat, 23 Oct 2021 15:16:57 +0100
Subject: [PATCH 2/3] Retain EventSource's original listener

---
 baselines/dom.generated.d.ts           |  2 ++
 baselines/serviceworker.generated.d.ts |  2 ++
 baselines/sharedworker.generated.d.ts  |  2 ++
 baselines/webworker.generated.d.ts     |  2 ++
 src/build/emitter.ts                   | 12 +++++++-----
 unittests/files/eventsource.ts         |  4 ++++
 6 files changed, 19 insertions(+), 5 deletions(-)
 create mode 100644 unittests/files/eventsource.ts

diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 7bfb1e28a..2df5ad63c 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -4929,8 +4929,10 @@ interface EventSource extends EventTarget {
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/baselines/serviceworker.generated.d.ts b/baselines/serviceworker.generated.d.ts
index 0780ac4b8..ed093cb4f 100644
--- a/baselines/serviceworker.generated.d.ts
+++ b/baselines/serviceworker.generated.d.ts
@@ -1301,8 +1301,10 @@ interface EventSource extends EventTarget {
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/baselines/sharedworker.generated.d.ts b/baselines/sharedworker.generated.d.ts
index c17c101bc..de24c60fd 100644
--- a/baselines/sharedworker.generated.d.ts
+++ b/baselines/sharedworker.generated.d.ts
@@ -1245,8 +1245,10 @@ interface EventSource extends EventTarget {
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/baselines/webworker.generated.d.ts b/baselines/webworker.generated.d.ts
index d108ca24f..fa215cfe3 100644
--- a/baselines/webworker.generated.d.ts
+++ b/baselines/webworker.generated.d.ts
@@ -1339,8 +1339,10 @@ interface EventSource extends EventTarget {
     readonly OPEN: number;
     addEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof EventSourceEventMap>(type: K, listener: (this: EventSource, ev: EventSourceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var EventSource: {
diff --git a/src/build/emitter.ts b/src/build/emitter.ts
index 139db0399..12e129831 100644
--- a/src/build/emitter.ts
+++ b/src/build/emitter.ts
@@ -1064,13 +1064,15 @@ export function emitWebIdl(
           : "EventListenerOptions";
       if (tryEmitTypedEventHandlerForInterface(addOrRemove, optionsType)) {
         // only emit the string event handler if we just emitted a typed handler
-        const listener =
-          i.name === "EventSource"
-            ? "(this: EventSource, event: MessageEvent) => any"
-            : "EventListenerOrEventListenerObject";
+
+        if (i.name === "EventSource") {
+          printer.printLine(
+            `${fPrefix}${addOrRemove}EventListener(type: string, listener: (this: EventSource, event: MessageEvent) => any, options?: boolean | ${optionsType}): void;`
+          );
+        }
 
         printer.printLine(
-          `${fPrefix}${addOrRemove}EventListener(type: string, listener: ${listener}, options?: boolean | ${optionsType}): void;`
+          `${fPrefix}${addOrRemove}EventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | ${optionsType}): void;`
         );
       }
     }
diff --git a/unittests/files/eventsource.ts b/unittests/files/eventsource.ts
new file mode 100644
index 000000000..57925866b
--- /dev/null
+++ b/unittests/files/eventsource.ts
@@ -0,0 +1,4 @@
+const source = new EventSource("/");
+
+source.addEventListener("custom", (event: MessageEvent) => {});
+source.addEventListener("with-handle-event", { handleEvent(event: Event) {} });

From 6a953ea976b6df04f516d8b037200affa03cd7a2 Mon Sep 17 00:00:00 2001
From: Alex Macleod <alex@macleod.io>
Date: Sat, 23 Oct 2021 16:24:44 +0100
Subject: [PATCH 3/3] Add test for MessageEvent being the default overload

---
 unittests/files/eventsource.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/unittests/files/eventsource.ts b/unittests/files/eventsource.ts
index 57925866b..f15fbcd06 100644
--- a/unittests/files/eventsource.ts
+++ b/unittests/files/eventsource.ts
@@ -1,4 +1,7 @@
 const source = new EventSource("/");
 
+source.addEventListener("custom", (event) => {
+  event.data; // MessageEvent specific
+});
 source.addEventListener("custom", (event: MessageEvent) => {});
 source.addEventListener("with-handle-event", { handleEvent(event: Event) {} });