From ab3057041acd66e38dd722fcbb2519429ed73c35 Mon Sep 17 00:00:00 2001
From: Dylan Piercey <dpiercey@ebay.com>
Date: Fri, 7 Aug 2020 12:10:02 -0700
Subject: [PATCH] fix: avoid writing unchanged virtual modules to disk

---
 src/loader/index.ts | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/loader/index.ts b/src/loader/index.ts
index 754f4ca..b4acc62 100644
--- a/src/loader/index.ts
+++ b/src/loader/index.ts
@@ -183,8 +183,19 @@ export default function(source: string): void | string {
             path.dirname(this.resourcePath),
             dep.virtualPath
           );
-          const virtualModules = getVirtualModules(this._compiler);
-          virtualModules.writeModule(virtualPath, dep.code);
+
+          // We don't want to hit the disk, but instead check if the viritual file was already written.
+          const existingContent =
+            this.fs._readFileStorage &&
+            this.fs._readFileStorage.data.get(virtualPath);
+
+          if (!existingContent || existingContent[1] !== dep.code) {
+            getVirtualModules(this._compiler).writeModule(
+              virtualPath,
+              dep.code
+            );
+          }
+
           dependencies.push(loadStr(dep.virtualPath));
         }
       }