feat: window.onunload (#3023)

2 files changed, 13 insertions, 0 deletions

diff --git a/js/globals.ts b/js/globals.ts
index 50f119971..b734b8da3 100644
--- a/js/globals.ts
+++ b/js/globals.ts
@@ -84,6 +84,7 @@ window.setTimeout = timers.setTimeout;
 window.setInterval = timers.setInterval;
 window.location = (undefined as unknown) as domTypes.Location;
 window.onload = undefined as undefined | Function;
+window.onunload = undefined as undefined | Function;
 // The following Crypto interface implementation is not up to par with the
 // standard https://www.w3.org/TR/WebCryptoAPI/#crypto-interface as it does not
 // yet incorporate the SubtleCrypto interface as its "subtle" property.
@@ -171,6 +172,16 @@ window.addEventListener(
     }
   }
 );
+// Registers the handler for window.onunload function.
+window.addEventListener(
+  "unload",
+  (e: domTypes.Event): void => {
+    const onunload = window.onunload;
+    if (typeof onunload === "function") {
+      onunload(e);
+    }
+  }
+);
 
 // below are interfaces that are available in TypeScript but
 // have different signatures
diff --git a/js/lib.deno_runtime.d.ts b/js/lib.deno_runtime.d.ts
index 1e220a29d..d0a720769 100644
--- a/js/lib.deno_runtime.d.ts
+++ b/js/lib.deno_runtime.d.ts
@@ -1248,6 +1248,7 @@ declare interface Window {
   setInterval: typeof timers.setInterval;
   location: domTypes.Location;
   onload: Function | undefined;
+  onunload: Function | undefined;
   crypto: Crypto;
   Blob: typeof blob.DenoBlob;
   File: domTypes.DomFileConstructor;
@@ -1294,6 +1295,7 @@ declare const setTimeout: typeof timers.setTimeout;
 declare const setInterval: typeof timers.setInterval;
 declare const location: domTypes.Location;
 declare const onload: Function | undefined;
+declare const onunload: Function | undefined;
 declare const crypto: Crypto;
 declare const Blob: typeof blob.DenoBlob;
 declare const File: domTypes.DomFileConstructor;