fix: updated CustomEvent.detail to be null when not defined

baselines/audioworklet.generated.d.ts

@@ -309,7 +309,7 @@ interface CustomEvent<T = any> extends Event {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/CustomEvent/detail)
      */
-    readonly detail: T;
+    readonly detail: T extends {} ? T : null;
     /**
      * @deprecated
      *

baselines/dom.generated.d.ts

@@ -5892,7 +5892,7 @@ interface CustomEvent<T = any> extends Event {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/CustomEvent/detail)
      */
-    readonly detail: T;
+    readonly detail: T extends {} ? T : null;
     /**
      * @deprecated
      *

baselines/serviceworker.generated.d.ts

@@ -1710,7 +1710,7 @@ interface CustomEvent<T = any> extends Event {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/CustomEvent/detail)
      */
-    readonly detail: T;
+    readonly detail: T extends {} ? T : null;
     /**
      * @deprecated
      *

baselines/sharedworker.generated.d.ts

@@ -1637,7 +1637,7 @@ interface CustomEvent<T = any> extends Event {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/CustomEvent/detail)
      */
-    readonly detail: T;
+    readonly detail: T extends {} ? T : null;
     /**
      * @deprecated
      *

baselines/webworker.generated.d.ts

@@ -1846,7 +1846,7 @@ interface CustomEvent<T = any> extends Event {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/CustomEvent/detail)
      */
-    readonly detail: T;
+    readonly detail: T extends {} ? T : null;
     /**
      * @deprecated
      *

inputfiles/overridingTypes.jsonc

@@ -536,7 +536,7 @@
                 "properties": {
                     "property": {
                         "detail": {
-                            "overrideType": "T"
+                            "overrideType": "T extends {} ? T : null"
                         }
                     }
                 },

unittests/files/customevents.ts

@@ -0,0 +1,16 @@
+new CustomEvent<null>("a").detail satisfies null;
+new CustomEvent<void>("b").detail satisfies null;
+new CustomEvent<undefined>("c").detail satisfies null;
+new CustomEvent<string>("d").detail satisfies string;
+new CustomEvent<string | undefined>("e").detail satisfies string | null;
+
+// @ts-expect-error Wrong type
+new CustomEvent<null>("a").detail satisfies undefined;
+// @ts-expect-error Wrong type
+new CustomEvent<void>("b").detail satisfies void;
+// @ts-expect-error Wrong type
+new CustomEvent<undefined>("c").detail satisfies undefined;
+// @ts-expect-error Wrong type
+new CustomEvent<string>("d").detail satisfies number;
+// @ts-expect-error Wrong type
+new CustomEvent<string | undefined>("e").detail satisfies string | undefined;

unittests/index.js

@@ -3,16 +3,24 @@ import { readdir } from "fs/promises";
 
 for (const filename of await readdir(new URL("files/", import.meta.url))) {
   if (filename.endsWith(".ts")) {
-    execSync(`npx tsc generated/dom.generated.d.ts unittests/files/${filename} --target es2020 --lib es2020 --types --noEmit`, {
-      stdio: "inherit"
-    });
+    execSync(
+      `npx tsc generated/dom.generated.d.ts unittests/files/${filename} --strict --strictNullChecks --target es2020 --lib es2020 --types --noEmit`,
+      {
+        stdio: "inherit",
+      }
+    );
   }
 }
 
-for (const filename of await readdir(new URL("files/audioworklet", import.meta.url))) {
+for (const filename of await readdir(
+  new URL("files/audioworklet", import.meta.url)
+)) {
   if (filename.endsWith(".ts")) {
-    execSync(`npx tsc generated/audioworklet.generated.d.ts unittests/files/audioworklet/${filename} --target es2020 --lib es2020 --types --noEmit`, {
-      stdio: "inherit"
-    });
+    execSync(
+      `npx tsc generated/audioworklet.generated.d.ts unittests/files/audioworklet/${filename} --strict --strictNullChecks --target es2020 --lib es2020 --types --noEmit`,
+      {
+        stdio: "inherit",
+      }
+    );
   }
 }