From a3ec84f09001a9154d1de315d073b9bd08bd9e93 Mon Sep 17 00:00:00 2001
From: David Walsh <dwalsh@mozilla.com>
Date: Mon, 9 Sep 2019 17:30:08 +0000
Subject: [PATCH] Bug 1579913 - Use CodeMirror Operations to improve inline
 preview performance r=jlast

Differential Revision: https://phabricator.services.mozilla.com/D45212

--HG--
extra : moz-landing-system : lando
---
 .../src/components/Editor/InlinePreviews.js       | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/devtools/client/debugger/src/components/Editor/InlinePreviews.js b/devtools/client/debugger/src/components/Editor/InlinePreviews.js
index 25d50d2d9f03..b9329274419c 100644
--- a/devtools/client/debugger/src/components/Editor/InlinePreviews.js
+++ b/devtools/client/debugger/src/components/Editor/InlinePreviews.js
@@ -42,10 +42,10 @@ class InlinePreviews extends Component<Props> {
     ) {
       return null;
     }
-
-    return (
-      <div>
-        {Object.keys(previews).map((line: string) => {
+    
+    let inlinePreviewRows;
+    editor.codeMirror.operation(() => {
+      inlinePreviewRows = Object.keys(previews).map((line: string) => {
           const lineNum: number = parseInt(line, 10);
           const numColumnBreakpoints = columnBreakpoints.filter(
             bp => bp.location.line === lineNum + 1
@@ -60,9 +60,10 @@ class InlinePreviews extends Component<Props> {
               numColumnBreakpoints={numColumnBreakpoints}
             />
           );
-        })}
-      </div>
-    );
+        });
+    });
+
+    return <div>{inlinePreviewRows}</div>;
   }
 }