events: lazy load perf_hooks for EventTarget

PR-URL: #33717 Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Zeyu Yang <[email protected]> Reviewed-By: Denys Otrishko <[email protected]> Reviewed-By: Juan José Arboleda <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Trivikram Kamat <[email protected]>
nodejs · Jun 16, 2020 · bc71278 · bc71278
1 parent 5536044
commit bc71278
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Showing 2 changed files with 9 additions and 6 deletions.
diff --git 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

diff --git a/test/parallel/test-bootstrap-modules.js b/test/parallel/test-bootstrap-modules.js
@@ -21,7 +21,6 @@ const expectedModules = new Set([
   'Internal Binding module_wrap',
   'Internal Binding native_module',
   'Internal Binding options',
-  'Internal Binding performance',
   'Internal Binding process_methods',
   'Internal Binding report',
   'Internal Binding string_decoder',
@@ -32,7 +31,6 @@ const expectedModules = new Set([
   'Internal Binding types',
   'Internal Binding url',
   'Internal Binding util',
-  'NativeModule async_hooks',
   'NativeModule buffer',
   'NativeModule events',
   'NativeModule fs',
@@ -50,7 +48,6 @@ const expectedModules = new Set([
   'NativeModule internal/fixed_queue',
   'NativeModule internal/fs/dir',
   'NativeModule internal/fs/utils',
-  'NativeModule internal/histogram',
   'NativeModule internal/idna',
   'NativeModule internal/linkedlist',
   'NativeModule internal/modules/run_main',
@@ -88,7 +85,6 @@ const expectedModules = new Set([
   'NativeModule internal/vm/module',
   'NativeModule internal/worker/js_transferable',
   'NativeModule path',
-  'NativeModule perf_hooks',
   'NativeModule timers',
   'NativeModule url',
   'NativeModule util',