From 76cb9c2a39d477a64824a985ade40507e3bbade1 Mon Sep 17 00:00:00 2001
From: Adam Mathes <adam@adammathes.com>
Date: Fri, 13 Feb 2026 21:34:48 -0800
Subject: feat(vanilla): add testing infrastructure and tests (NK-wjnczv)

---
 vanilla/node_modules/stackback/index.js | 46 +++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 vanilla/node_modules/stackback/index.js

(limited to 'vanilla/node_modules/stackback/index.js')

diff --git a/vanilla/node_modules/stackback/index.js b/vanilla/node_modules/stackback/index.js
new file mode 100644
index 0000000..8b87042
--- /dev/null
+++ b/vanilla/node_modules/stackback/index.js
@@ -0,0 +1,46 @@
+
+// v8 builtin format stack trace
+// for when there was no previous prepareStackTrace function to call
+var FormatStackTrace = require('./formatstack');
+
+// some notes on the behavior below:
+// because the 'stack' member is a one shot access variable (the raw stack is
+// formatted on accessing it)
+// we try to avoid modifying what the user would have wanted
+// thus we use the previous value for prepareStackTrace
+//
+// The reason we store the callsite variable is because prepareStackTrace
+// will not be called again once it has been called for a given error object
+// but we want to support getting the stack out of the error multiple times (cause why not)
+module.exports = function(err) {
+
+    // save original stacktrace
+    var save = Error.prepareStackTrace;
+
+    // replace capture with our function
+    Error.prepareStackTrace =  function(err, trace) {
+
+        // cache stack frames so we don't have to get them again
+        // use a non-enumerable property
+        Object.defineProperty(err, '_sb_callsites', {
+            value: trace
+        });
+
+        return (save || FormatStackTrace)(err, trace);
+    };
+
+    // force capture of the stack frames
+    err.stack;
+
+    // someone already asked for the stack so we can't do this trick
+    // TODO fallback to string parsing?
+    if (!err._sb_callsites) {
+        return [];
+    }
+
+    // return original capture function
+    Error.prepareStackTrace = save;
+
+    return err._sb_callsites;
+};
+
-- 
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