timers: compare to null not falsey

lib/timers.js

@@ -652,7 +652,7 @@ function ImmediateList() {
 // Appends an item to the end of the linked list, adjusting the current tail's
 // previous and next pointers where applicable
 ImmediateList.prototype.append = function(item) {
-  if (this.tail) {
+  if (this.tail !== null) {
     this.tail._idleNext = item;
     item._idlePrev = this.tail;
   } else {
@@ -664,11 +664,11 @@ ImmediateList.prototype.append = function(item) {
 // Removes an item from the linked list, adjusting the pointers of adjacent
 // items and the linked list's head or tail pointers as necessary
 ImmediateList.prototype.remove = function(item) {
-  if (item._idleNext) {
+  if (item._idleNext !== null) {
     item._idleNext._idlePrev = item._idlePrev;
   }
 
-  if (item._idlePrev) {
+  if (item._idlePrev !== null) {
     item._idlePrev._idleNext = item._idleNext;
   }
 
@@ -694,7 +694,7 @@ function processImmediate() {
   // immediate callbacks are executed
   immediateQueue.head = immediateQueue.tail = null;
 
-  while (immediate) {
+  while (immediate !== null) {
     domain = immediate.domain;
 
     if (!immediate._onImmediate) {
@@ -715,7 +715,7 @@ function processImmediate() {
 
     // If `clearImmediate(immediate)` wasn't called from the callback, use the
     // `immediate`'s next item
-    if (immediate._idleNext)
+    if (immediate._idleNext !== null)
       immediate = immediate._idleNext;
     else
       immediate = next;
@@ -747,11 +747,11 @@ function tryOnImmediate(immediate, oldTail) {
       }
     }
 
-    if (threw && immediate._idleNext) {
+    if (threw && immediate._idleNext !== null) {
       // Handle any remaining on next tick, assuming we're still alive to do so.
       const curHead = immediateQueue.head;
       const next = immediate._idleNext;
-      if (curHead) {
+      if (curHead !== null) {
         curHead._idlePrev = oldTail;
         oldTail._idleNext = curHead;
         next._idlePrev = null;