2 files changed, 48 insertions, 9 deletions
diff --git a/extensions/webidl/00_webidl.js b/extensions/webidl/00_webidl.js
index 49f586135..a54d2fe6e 100644
--- a/extensions/webidl/00_webidl.js
+++ b/extensions/webidl/00_webidl.js
@@ -566,6 +566,7 @@
   converters["sequence<double>"] = createSequenceConverter(
     converters["double"],
   );
+  converters["Promise<undefined>"] = createPromiseConverter(() => undefined);
 
   function requiredArguments(length, required, opts = {}) {
     if (length < required) {
@@ -578,11 +579,6 @@
     }
   }
 
-  function isEmptyObject(V) {
-    for (const _ in V) return false;
-    return true;
-  }
-
   function createDictionaryConverter(name, ...dictionaries) {
     let hasRequiredKey = false;
     const allMembers = [];
@@ -642,10 +638,8 @@
 
       const idlDict = { ...defaultValues };
 
-      // NOTE: fast path Null and Undefined and empty objects.
-      if (
-        (V === undefined || V === null || isEmptyObject(V)) && !hasRequiredKey
-      ) {
+      // NOTE: fast path Null and Undefined.
+      if ((V === undefined || V === null) && !hasRequiredKey) {
         return idlDict;
       }
 
@@ -774,6 +768,31 @@
     };
   }
 
+  function createPromiseConverter(converter) {
+    return (V, opts) => Promise.resolve(V).then((V) => converter(V, opts));
+  }
+
+  function invokeCallbackFunction(
+    callable,
+    args,
+    thisArg,
+    returnValueConverter,
+    opts,
+  ) {
+    try {
+      const rv = Reflect.apply(callable, thisArg, args);
+      return returnValueConverter(rv, {
+        prefix: opts.prefix,
+        context: "return value",
+      });
+    } catch (err) {
+      if (opts.returnsPromise === true) {
+        return Promise.reject(err);
+      }
+      throw err;
+    }
+  }
+
   const brand = Symbol("[[webidl.brand]]");
 
   function createInterfaceConverter(name, prototype) {
@@ -927,6 +946,8 @@
     createNullableConverter,
     createSequenceConverter,
     createRecordConverter,
+    createPromiseConverter,
+    invokeCallbackFunction,
     createInterfaceConverter,
     brand,
     createBranded,
diff --git a/extensions/webidl/internal.d.ts b/extensions/webidl/internal.d.ts
index 2d23f0ed2..4d0f1ad45 100644
--- a/extensions/webidl/internal.d.ts
+++ b/extensions/webidl/internal.d.ts
@@ -249,6 +249,24 @@ declare namespace globalThis {
       ): (v: any, opts: ValueConverterOpts) => T[];
 
       /**
+       * Create a converter that converts a Promise of the inner type.
+       */
+      declare function createPromiseConverter<T>(
+        converter: (v: any, opts: ValueConverterOpts) => T,
+      ): (v: any, opts: ValueConverterOpts) => Promise<T>;
+
+      /**
+       * Invoke a callback function.
+       */
+      declare function invokeCallbackFunction<T>(
+        callable: (...args: any) => any,
+        args: any[],
+        thisArg: any,
+        returnValueConverter: (v: any, opts: ValueConverterOpts) => T,
+        opts: ConverterOpts & { returnsPromise?: boolean },
+      ): T;
+
+      /**
        * Throw an illegal constructor error.
        */
       declare function illegalConstructor(): never;