From 9af18c2fd07129171fbacd528ad109adfdb9f784 Mon Sep 17 00:00:00 2001
From: Benedikt Meurer <bmeurer@google.com>
Date: Mon, 28 Jan 2019 15:14:05 +0100
Subject: [PATCH] perf(core): be more consistent about typeof checks (#28400)

When testing whether `value` is an object, use the ideal sequence of
strictly not equal to `null` followed by `typeof value === 'object'`
consistently. Specifically there's no point in using double equal with
`null` since `undefined` is ruled out by the `typeof` check.

Also avoid the unnecessary ToBoolean check on `value.ngOnDestroy` in
`hasOnDestroy()`, since the `typeof value.ngOnDestroy === 'function'`
will only let closures pass and all closures are truish (with the
notable exception of `document.all`, but that shouldn't be relevant
for the `ngOnDestroy` hook).

PR Close #28400
---
 packages/core/src/di/r3_injector.ts              | 4 ++--
 packages/core/src/render3/interfaces/injector.ts | 2 +-
 packages/core/src/view/ng_module.ts              | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/core/src/di/r3_injector.ts b/packages/core/src/di/r3_injector.ts
index 2f16c70f6d..c618d5d5b3 100644
--- a/packages/core/src/di/r3_injector.ts
+++ b/packages/core/src/di/r3_injector.ts
@@ -435,7 +435,7 @@ function deepForEach<T>(input: (T | any[])[], fn: (value: T) => void): void {
 }
 
 function isValueProvider(value: SingleProvider): value is ValueProvider {
-  return value && typeof value == 'object' && USE_VALUE in value;
+  return value !== null && typeof value == 'object' && USE_VALUE in value;
 }
 
 function isExistingProvider(value: SingleProvider): value is ExistingProvider {
@@ -456,7 +456,7 @@ function hasDeps(value: ClassProvider | ConstructorProvider | StaticClassProvide
 }
 
 function hasOnDestroy(value: any): value is OnDestroy {
-  return typeof value === 'object' && value != null && (value as OnDestroy).ngOnDestroy &&
+  return value !== null && typeof value === 'object' &&
       typeof(value as OnDestroy).ngOnDestroy === 'function';
 }
 
diff --git a/packages/core/src/render3/interfaces/injector.ts b/packages/core/src/render3/interfaces/injector.ts
index f93fd5f18a..9b8a6695e8 100644
--- a/packages/core/src/render3/interfaces/injector.ts
+++ b/packages/core/src/render3/interfaces/injector.ts
@@ -248,7 +248,7 @@ export class NodeInjectorFactory {
 const FactoryPrototype = NodeInjectorFactory.prototype;
 export function isFactory(obj: any): obj is NodeInjectorFactory {
   // See: https://jsperf.com/instanceof-vs-getprototypeof
-  return obj != null && typeof obj == 'object' && Object.getPrototypeOf(obj) == FactoryPrototype;
+  return obj !== null && typeof obj == 'object' && Object.getPrototypeOf(obj) == FactoryPrototype;
 }
 
 // Note: This hack is necessary so we don't erroneously get a circular dependency
diff --git a/packages/core/src/view/ng_module.ts b/packages/core/src/view/ng_module.ts
index cfd5462e92..a09f79943d 100644
--- a/packages/core/src/view/ng_module.ts
+++ b/packages/core/src/view/ng_module.ts
@@ -158,7 +158,7 @@ function _createProviderInstance(ngModule: NgModuleData, providerDef: NgModulePr
   // avoided if possible. The sequence of checks here determines whether ngOnDestroy needs to be
   // checked. It might not if the `injectable` isn't an object or if NodeFlags.OnDestroy is already
   // set (ngOnDestroy was detected statically).
-  if (injectable !== UNDEFINED_VALUE && injectable != null && typeof injectable === 'object' &&
+  if (injectable !== UNDEFINED_VALUE && injectable !== null && typeof injectable === 'object' &&
       !(providerDef.flags & NodeFlags.OnDestroy) && typeof injectable.ngOnDestroy === 'function') {
     providerDef.flags |= NodeFlags.OnDestroy;
   }