From f436ae45e5f52add12af8ea4f9748f56ce0b9404 Mon Sep 17 00:00:00 2001
From: JAPER <eric.mourant@japer.technology>
Date: Tue, 2 Sep 2025 09:57:05 +1000
Subject: [PATCH] Handle errors from context functions

---
 README.md                       |  2 ++
 collectInvocation.js            | 11 ++++++++++-
 tests/collectInvocation.test.js | 16 ++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 9d57683..5aa128c 100644
--- a/README.md
+++ b/README.md
@@ -198,3 +198,5 @@ aws lambda invoke \
 ## Debugging
 
 Set `DEBUG=1` (or any non-empty value) to enable additional log output. This can help troubleshoot event dispatching and handler execution.
+
+When invocation data is collected, functions on the `context` object are invoked. If a context function throws an error, its message is captured and included in the logged context instead of halting execution.
diff --git a/collectInvocation.js b/collectInvocation.js
index 4021fa2..4a11b0a 100644
--- a/collectInvocation.js
+++ b/collectInvocation.js
@@ -3,6 +3,7 @@
  *
  * The raw `context` object exposes functions, so we copy its enumerable
  * properties while invoking any functions to capture their returned values.
+ * If a function throws, its error message is stored instead of aborting.
  * This keeps test snapshots stable and avoids leaking functions.
  *
  * @param {object} event - Event payload provided to the Lambda.
@@ -14,7 +15,15 @@ export default function collectInvocation(event, context, handlerType) {
   const ctx = {};
   if (context) {
     for (const [key, value] of Object.entries(context)) {
-      ctx[key] = typeof value === 'function' ? value.call(context) : value;
+      if (typeof value === 'function') {
+        try {
+          ctx[key] = value.call(context);
+        } catch (err) {
+          ctx[key] = err && err.message ? err.message : String(err);
+        }
+      } else {
+        ctx[key] = value;
+      }
     }
   }
   return { event, context: ctx, handlerType };
diff --git a/tests/collectInvocation.test.js b/tests/collectInvocation.test.js
index 4f7f8af..f4bc29c 100644
--- a/tests/collectInvocation.test.js
+++ b/tests/collectInvocation.test.js
@@ -21,4 +21,20 @@ describe('collectInvocation', () => {
       handlerType: 'test'
     });
   });
+
+  test('handles context functions that throw', () => {
+    const event = {};
+    const context = {
+      ok: () => 'good',
+      fail() { throw new Error('boom'); }
+    };
+
+    const result = collectInvocation(event, context, 'test');
+
+    expect(result).toEqual({
+      event,
+      context: { ok: 'good', fail: 'boom' },
+      handlerType: 'test'
+    });
+  });
 });