diff --git a/packages/core/src/di/injector.ts b/packages/core/src/di/injector.ts
index 6efee5d6f7..1bcb4d66f8 100644
--- a/packages/core/src/di/injector.ts
+++ b/packages/core/src/di/injector.ts
@@ -230,7 +230,7 @@ function recursivelyProcessProviders(records: Map<any, Record>, provider: Static
   let scope: string|null = null;
   if (provider) {
     provider = resolveForwardRef(provider);
-    if (provider instanceof Array) {
+    if (Array.isArray(provider)) {
       // if we have an array recurse into the array
       for (let i = 0; i < provider.length; i++) {
         scope = recursivelyProcessProviders(records, provider[i]) || scope;
@@ -359,7 +359,7 @@ function computeDeps(provider: StaticProvider): DependencyRecord[] {
     for (let i = 0; i < providerDeps.length; i++) {
       let options = OptionFlags.Default;
       let token = resolveForwardRef(providerDeps[i]);
-      if (token instanceof Array) {
+      if (Array.isArray(token)) {
         for (let j = 0, annotations = token; j < annotations.length; j++) {
           const annotation = annotations[j];
           if (annotation instanceof Optional || annotation == Optional) {
diff --git a/packages/core/src/di/injector_compatibility.ts b/packages/core/src/di/injector_compatibility.ts
index 096122c0a9..e8ddaa7d33 100644
--- a/packages/core/src/di/injector_compatibility.ts
+++ b/packages/core/src/di/injector_compatibility.ts
@@ -227,7 +227,7 @@ export function formatError(
     text: string, obj: any, injectorErrorName: string, source: string | null = null): string {
   text = text && text.charAt(0) === '\n' && text.charAt(1) == NO_NEW_LINE ? text.substr(2) : text;
   let context = stringify(obj);
-  if (obj instanceof Array) {
+  if (Array.isArray(obj)) {
     context = obj.map(stringify).join(' -> ');
   } else if (typeof obj === 'object') {
     let parts = <string[]>[];
diff --git a/packages/core/src/di/reflective_provider.ts b/packages/core/src/di/reflective_provider.ts
index 96286d9594..11ff444555 100644
--- a/packages/core/src/di/reflective_provider.ts
+++ b/packages/core/src/di/reflective_provider.ts
@@ -189,7 +189,7 @@ function _normalizeProviders(
     } else if (b && typeof b == 'object' && (b as any).provide !== undefined) {
       res.push(b as NormalizedProvider);
 
-    } else if (b instanceof Array) {
+    } else if (Array.isArray(b)) {
       _normalizeProviders(b, res);
 
     } else {
diff --git a/packages/core/src/util/stringify.ts b/packages/core/src/util/stringify.ts
index 0af107a1f4..138ce95f62 100644
--- a/packages/core/src/util/stringify.ts
+++ b/packages/core/src/util/stringify.ts
@@ -11,7 +11,7 @@ export function stringify(token: any): string {
     return token;
   }
 
-  if (token instanceof Array) {
+  if (Array.isArray(token)) {
     return '[' + token.map(stringify).join(', ') + ']';
   }
 
diff --git a/packages/core/test/application_ref_spec.ts b/packages/core/test/application_ref_spec.ts
index 6a4dbb83bb..d27a32a60f 100644
--- a/packages/core/test/application_ref_spec.ts
+++ b/packages/core/test/application_ref_spec.ts
@@ -49,7 +49,7 @@ class SomeComponent {
     function createModule(options: CreateModuleOptions): Type<any>;
     function createModule(providersOrOptions: any[] | CreateModuleOptions | undefined): Type<any> {
       let options: CreateModuleOptions = {};
-      if (providersOrOptions instanceof Array) {
+      if (Array.isArray(providersOrOptions)) {
         options = {providers: providersOrOptions};
       } else {
         options = providersOrOptions || {};
diff --git a/packages/core/testing/src/metadata_overrider.ts b/packages/core/testing/src/metadata_overrider.ts
index a2c6581889..4a5bf78467 100644
--- a/packages/core/testing/src/metadata_overrider.ts
+++ b/packages/core/testing/src/metadata_overrider.ts
@@ -48,7 +48,7 @@ function removeMetadata(metadata: StringMap, remove: any, references: Map<any, s
   const removeObjects = new Set<string>();
   for (const prop in remove) {
     const removeValue = remove[prop];
-    if (removeValue instanceof Array) {
+    if (Array.isArray(removeValue)) {
       removeValue.forEach(
           (value: any) => { removeObjects.add(_propHashKey(prop, value, references)); });
     } else {
@@ -58,7 +58,7 @@ function removeMetadata(metadata: StringMap, remove: any, references: Map<any, s
 
   for (const prop in metadata) {
     const propValue = metadata[prop];
-    if (propValue instanceof Array) {
+    if (Array.isArray(propValue)) {
       metadata[prop] = propValue.filter(
           (value: any) => !removeObjects.has(_propHashKey(prop, value, references)));
     } else {
@@ -73,7 +73,7 @@ function addMetadata(metadata: StringMap, add: any) {
   for (const prop in add) {
     const addValue = add[prop];
     const propValue = metadata[prop];
-    if (propValue != null && propValue instanceof Array) {
+    if (propValue != null && Array.isArray(propValue)) {
       metadata[prop] = propValue.concat(addValue);
     } else {
       metadata[prop] = addValue;