From 55504e2c332a4b099692899ee2587302b470c6a1 Mon Sep 17 00:00:00 2001
From: Ward Peeters <ward@coding-tech.com>
Date: Wed, 20 Mar 2019 22:06:20 +0100
Subject: [PATCH] fix(gatsby): quick check if string looks like a date

---
 packages/gatsby/src/schema/types/date.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/gatsby/src/schema/types/date.js b/packages/gatsby/src/schema/types/date.js
index 230df593029dc..b83c425670bb8 100644
--- a/packages/gatsby/src/schema/types/date.js
+++ b/packages/gatsby/src/schema/types/date.js
@@ -99,8 +99,13 @@ const GraphQLDate = new GraphQLScalarType({
 // Check if this is a date.
 // All the allowed ISO 8601 date-time formats used.
 function isDate(value) {
+  // quick check if value does not look like a date
+  if (typeof value === `number` || !/^\d{4}/.test(value)) {
+    return false
+  }
+
   const momentDate = moment.utc(value, ISO_8601_FORMAT, true)
-  return momentDate.isValid() && typeof value !== `number`
+  return momentDate.isValid()
 }
 
 const formatDate = ({