perf_hooks: refactor to avoid unsafe array iteration

aduh95 · danielleadams · commit a258bc9b70ed · 2021-01-12T07:10:35.000-05:00
PR-URL: #36723 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Rich Trott <rtrott@gmail.com>
diff --git a/lib/perf_hooks.js b/lib/perf_hooks.js
@@ -3,6 +3,7 @@
 const {
   ArrayIsArray,
   ArrayPrototypeFilter,
+  ArrayPrototypeForEach,
   ArrayPrototypeIncludes,
   ArrayPrototypeMap,
   ArrayPrototypePush,
@@ -375,13 +376,13 @@ class PerformanceObserver {
   disconnect() {
     const observerCountsGC = observerCounts[NODE_PERFORMANCE_ENTRY_TYPE_GC];
     const types = this[kTypes];
-    for (const key of ObjectKeys(types)) {
+    ArrayPrototypeForEach(ObjectKeys(types), (key) => {
       const item = types[key];
       if (item) {
         L.remove(item);
         observerCounts[key]--;
       }
-    }
+    });
     this[kTypes] = {};
     if (observerCountsGC === 1 &&
       observerCounts[NODE_PERFORMANCE_ENTRY_TYPE_GC] === 0) {
@@ -408,14 +409,14 @@ class PerformanceObserver {
     this[kBuffer][kEntries] = [];
     L.init(this[kBuffer][kEntries]);
     this[kBuffering] = Boolean(options.buffered);
-    for (const entryType of filteredEntryTypes) {
+    ArrayPrototypeForEach(filteredEntryTypes, (entryType) => {
       const list = getObserversList(entryType);
-      if (this[kTypes][entryType]) continue;
+      if (this[kTypes][entryType]) return;
       const item = { obs: this };
       this[kTypes][entryType] = item;
       L.append(list, item);
       observerCounts[entryType]++;
-    }
+    });
     if (observerCountsGC === 0 &&
       observerCounts[NODE_PERFORMANCE_ENTRY_TYPE_GC] === 1) {
       installGarbageCollectionTracking();
@@ -640,6 +641,7 @@ function sortedInsert(list, entry) {
 }
 
 class ELDHistogram extends Histogram {
+  constructor(i) { super(i); } // eslint-disable-line no-useless-constructor
   enable() { return this[kHandle].enable(); }
   disable() { return this[kHandle].disable(); }
 }
