From f93a8c3c93eb03e65198b340f3ac551af8f6baac Mon Sep 17 00:00:00 2001
From: Dobes Vandermeer <dobesv@gmail.com>
Date: Wed, 5 Sep 2018 09:26:51 -0700
Subject: [PATCH] fix(cursor): allow `$meta` based sort when passing an array
 to `sort()`

You may pass an object with a `$meta` key in place of the order parameter to `sort`.  The previous code would incorrectly reject this input as illegal.  See https://docs.mongodb.com/manual/reference/method/cursor.sort/#sort-metadata for documentation.
---
 lib/cursor.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/cursor.js b/lib/cursor.js
index 69293213ec..4a0b815f67 100644
--- a/lib/cursor.js
+++ b/lib/cursor.js
@@ -557,7 +557,7 @@ Cursor.prototype.sort = function(keyOrList, direction) {
           value[1] = 1;
         } else if (x[1] === 'desc') {
           value[1] = -1;
-        } else if (x[1] === 1 || x[1] === -1) {
+        } else if (x[1] === 1 || x[1] === -1 || x[1].$meta) {
           value[1] = x[1];
         } else {
           throw new MongoError(