From 7169dc04ee938fd3b52e5a0e596dd4eb97a02acf Mon Sep 17 00:00:00 2001
From: James M Snell <jasnell@gmail.com>
Date: Wed, 3 Jun 2020 18:13:01 -0700
Subject: [PATCH] events: lazy load perf_hooks for EventTarget
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PR-URL: https://github.com/nodejs/node/pull/33717
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
---
 lib/internal/event_target.js | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/internal/event_target.js b/lib/internal/event_target.js
index 8641129b132914..3df88cedf58a3d 100644
--- a/lib/internal/event_target.js
+++ b/lib/internal/event_target.js
@@ -19,7 +19,6 @@ const {
   }
 } = require('internal/errors');
 
-const perf_hooks = require('perf_hooks');
 const { customInspectSymbol } = require('internal/util');
 const { inspect } = require('util');
 
@@ -30,11 +29,19 @@ const kTarget = Symbol('kTarget');
 const kNewListener = Symbol('kNewListener');
 const kRemoveListener = Symbol('kRemoveListener');
 
+// Lazy load perf_hooks to avoid the additional overhead on startup
+let perf_hooks;
+function lazyNow() {
+  if (perf_hooks === undefined)
+    perf_hooks = require('perf_hooks');
+  return perf_hooks.performance.now();
+}
+
 class Event {
   #type = undefined;
   #defaultPrevented = false;
   #cancelable = false;
-  #timestamp = perf_hooks.performance.now();
+  #timestamp = lazyNow();
 
   // None of these are currently used in the Node.js implementation
   // of EventTarget because there is no concept of bubbling or