Fix serialization of Dates with expanded ISO years

index.js

@@ -319,7 +319,7 @@ module.exports = function serialize(obj, options) {
         if (type === 'D') {
             // Validate ISO string format to prevent code injection via spoofed toISOString()
             var isoStr = String(dates[valueIndex].toISOString());
-            if (!/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d{3})?Z$/.test(isoStr)) {
+            if (!/^(?:\d{4}|[+-]\d{6})-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(\.\d{3})?Z$/.test(isoStr)) {
                 throw new TypeError('Invalid Date ISO string');
             }
             return "new Date(\"" + isoStr + "\")";

test/unit/expanded-date-years.js

@@ -0,0 +1,14 @@
+const { describe, it } = require('node:test');
+const { strictEqual } = require('node:assert');
+const serialize = require('../../');
+
+describe('Dates with expanded ISO years', function () {
+    for (const timestamp of [-8640000000000000, -62198755200000, 253402300800000, 8640000000000000]) {
+        it('round trips timestamp ' + timestamp, function () {
+            const date = new Date(timestamp);
+            const decoded = eval('(' + serialize(date) + ')');
+            strictEqual(decoded.getTime(), date.getTime());
+            strictEqual(decoded.toISOString(), date.toISOString());
+        });
+    }
+});