From 1948597bf82e4d5034d6a28b734bbde4301b0702 Mon Sep 17 00:00:00 2001
From: halfnelson <dpershouse@gmail.com>
Date: Sun, 24 Feb 2019 11:55:47 +1000
Subject: [PATCH] Some input filesystems don't implement purge

---
 lib/virtual.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/virtual.js b/lib/virtual.js
index b4f70b4f..7dec0eef 100644
--- a/lib/virtual.js
+++ b/lib/virtual.js
@@ -12,7 +12,9 @@ function VirtualModulesPlugin(compiler) {
 		var originalPurge = compiler.inputFileSystem.purge;
 
 		compiler.inputFileSystem.purge = function() {
-			originalPurge.call(this, arguments);
+			if (originalPurge) {
+				originalPurge.call(this, arguments);
+			}
 			if (this._virtualFiles) {
 				Object.keys(this._virtualFiles).forEach(
 					function(file) {