From 9cbb7ea29c93de195a943c5c65c60eb258638a4d Mon Sep 17 00:00:00 2001
From: TypeScript Bot <ts_bot@rcavanaugh.com>
Date: Wed, 4 Sep 2019 11:44:31 -0700
Subject: [PATCH] Cherry-pick PR #33225 into release-3.6 (#33226)

Component commits:
541e96ec9f Handle browserify-ignored module result for etw logger
---
 src/compiler/perfLogger.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/compiler/perfLogger.ts b/src/compiler/perfLogger.ts
index 974e231d15d4b..5696a97ad423d 100644
--- a/src/compiler/perfLogger.ts
+++ b/src/compiler/perfLogger.ts
@@ -36,8 +36,8 @@ namespace ts {
         etwModule = undefined;
     }
 
-    /** Performance logger that will generate ETW events if possible */
-    export const perfLogger: PerfLogger = etwModule ? etwModule : nullLogger;
+    /** Performance logger that will generate ETW events if possible - check for `logEvent` member, as `etwModule` will be `{}` when browserified */
+    export const perfLogger: PerfLogger = etwModule && etwModule.logEvent ? etwModule : nullLogger;
 
     perfLogger.logInfoEvent(`Starting TypeScript v${versionMajorMinor} with command line: ${JSON.stringify(process.argv)}`);
 }