From 01af755d18decb5669aa37bddb7a090569286553 Mon Sep 17 00:00:00 2001
From: Drew Gross <drew.a.gross@gmail.com>
Date: Thu, 31 Mar 2016 18:49:58 -0700
Subject: [PATCH] Accept only bool for $exists in LiveQuery

---
 src/LiveQuery/QueryTools.js | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/LiveQuery/QueryTools.js b/src/LiveQuery/QueryTools.js
index adbc4deece..8a47f25c79 100644
--- a/src/LiveQuery/QueryTools.js
+++ b/src/LiveQuery/QueryTools.js
@@ -208,6 +208,11 @@ function matchesKeyConstraints(object, key, constraints) {
       case '$exists':
         let propertyExists = typeof object[key] !== 'undefined';
         let existenceIsRequired = constraints['$exists'];
+        if (typeof constraints['$exists'] !== 'boolean') {
+          // The SDK will never submit a non-boolean for $exists, but if someone
+          // tries to submit a non-boolean for $exits outside the SDKs, just ignore it.
+          break;
+        }
         if ((!propertyExists && existenceIsRequired) || (propertyExists && !existenceIsRequired)) {
           return false;
         }