From 06691f6a34c3d17ef5ea6e4fd4e429c0c1962fa2 Mon Sep 17 00:00:00 2001
From: Katherine Walker <kvwalker@users.noreply.github.com>
Date: Tue, 22 May 2018 15:29:46 -0400
Subject: [PATCH] fix(parsing): support encoding and decoding RegExps

Fixes NODE-1464
---
 lib/ext_json.js              | 8 +++++++-
 test/extend_mongodb_tests.js | 9 +++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/ext_json.js b/lib/ext_json.js
index b92f79c..3d12f41 100644
--- a/lib/ext_json.js
+++ b/lib/ext_json.js
@@ -230,8 +230,14 @@ function serializeDocument(doc, options) {
     } else if (val != null && typeof val === 'object') {
       _doc[name] = serializeDocument(val, options);
     }
-
     _doc[name] = serializeValue(val, options);
+    if (val instanceof RegExp) {
+      let flags = val.flags;
+      if (flags === undefined) {
+        flags = val.toString().match(/[gimuy]*$/)[0];
+      }
+      _doc[name] = codecs['BSONRegExp'].toExtendedJSON({ pattern: val.source, options: flags });
+    }
   }
 
   return _doc;
diff --git a/test/extend_mongodb_tests.js b/test/extend_mongodb_tests.js
index 40c2697..493468d 100644
--- a/test/extend_mongodb_tests.js
+++ b/test/extend_mongodb_tests.js
@@ -204,6 +204,15 @@ describe('Extended JSON', function() {
           date: dt
         });
       });
+
+      it('should allow regexp', function() {
+        const parsedRegExp = extJSON.stringify({ test: /some-regex/i }, { relaxed: true });
+        const parsedBSONRegExp = extJSON.stringify(
+          { test: new BSONRegExp('some-regex', 'i') },
+          { relaxed: true }
+        );
+        expect(parsedRegExp).to.eql(parsedBSONRegExp);
+      });
     });
   });
 });