Handle context prototype methods in invocation collector

collectInvocation.js

@@ -14,7 +14,7 @@
 export default function collectInvocation(event, context, handlerType) {
   const ctx = {};
   if (context) {
-    for (const [key, value] of Object.entries(context)) {
+    const handle = (key, value) => {
       if (typeof value === 'function') {
         try {
           ctx[key] = value.call(context);
@@ -24,6 +24,20 @@ export default function collectInvocation(event, context, handlerType) {
       } else {
         ctx[key] = value;
       }
+    };
+
+    for (const [key, value] of Object.entries(context)) {
+      handle(key, value);
+    }
+
+    const proto = Object.getPrototypeOf(context);
+    if (proto && proto !== Object.prototype) {
+      for (const key of Reflect.ownKeys(proto)) {
+        if (key === 'constructor' || Object.prototype.hasOwnProperty.call(ctx, key)) {
+          continue;
+        }
+        handle(key, context[key]);
+      }
     }
   }
   return { event, context: ctx, handlerType };

tests/collectInvocation.test.js

@@ -41,4 +41,28 @@ describe('collectInvocation', () => {
       handlerType: 'test'
     });
   });
+
+  test('captures prototype methods', () => {
+    const event = {};
+    class ProtoCtx {
+      protoMethod() { return 'proto'; }
+      protoFail() { throw new Error('oops'); }
+    }
+    const context = new ProtoCtx();
+    context.awsRequestId = 'req-2';
+    context.own = () => 'own';
+
+    const result = collectInvocation(event, context, 'test');
+
+    expect(result).toEqual({
+      event,
+      context: {
+        awsRequestId: 'req-2',
+        own: 'own',
+        protoMethod: 'proto',
+        protoFail: 'oops'
+      },
+      handlerType: 'test'
+    });
+  });
 });