From c0d04175ff1cea8f562f80448bb60ea83b278ae4 Mon Sep 17 00:00:00 2001
From: Alan Agius <alanagius@google.com>
Date: Mon, 5 Dec 2022 16:18:26 +0000
Subject: [PATCH] refactor(core): simplify array flatten logic (#48358)

We can now use modern Javascript to get the same result.

PR Close #48358
---
 packages/core/src/di/create_injector.ts       |  1 -
 packages/core/src/util/array_utils.ts         | 20 ++-----------------
 .../router/bundle.golden_symbols.json         |  3 ---
 3 files changed, 2 insertions(+), 22 deletions(-)

diff --git a/packages/core/src/di/create_injector.ts b/packages/core/src/di/create_injector.ts
index 68f96d214a4e7..36274c4241d91 100644
--- a/packages/core/src/di/create_injector.ts
+++ b/packages/core/src/di/create_injector.ts
@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {flatten} from '../util/array_utils';
 import {EMPTY_ARRAY} from '../util/empty';
 import {stringify} from '../util/stringify';
 
diff --git a/packages/core/src/util/array_utils.ts b/packages/core/src/util/array_utils.ts
index 4c1ed40a47ae9..f16953b044b14 100644
--- a/packages/core/src/util/array_utils.ts
+++ b/packages/core/src/util/array_utils.ts
@@ -32,27 +32,11 @@ export function arrayEquals<T>(a: T[], b: T[], identityAccessor?: (value: T) =>
   return true;
 }
 
-
 /**
  * Flattens an array.
  */
-export function flatten(list: any[], dst?: any[]): any[] {
-  if (dst === undefined) dst = list;
-  for (let i = 0; i < list.length; i++) {
-    let item = list[i];
-    if (Array.isArray(item)) {
-      // we need to inline it.
-      if (dst === list) {
-        // Our assumption that the list was already flat was wrong and
-        // we need to clone flat since we need to write to it.
-        dst = list.slice(0, i);
-      }
-      flatten(item, dst);
-    } else if (dst !== list) {
-      dst.push(item);
-    }
-  }
-  return dst;
+export function flatten(list: any[]): any[] {
+  return list.flat(Number.POSITIVE_INFINITY);
 }
 
 export function deepForEach<T>(input: (T|any[])[], fn: (value: T) => void): void {
diff --git a/packages/core/test/bundling/router/bundle.golden_symbols.json b/packages/core/test/bundling/router/bundle.golden_symbols.json
index 511c16da48c4f..5849d985071e6 100644
--- a/packages/core/test/bundling/router/bundle.golden_symbols.json
+++ b/packages/core/test/bundling/router/bundle.golden_symbols.json
@@ -1016,9 +1016,6 @@
   {
     "name": "first"
   },
-  {
-    "name": "flatten"
-  },
   {
     "name": "flatten2"
   },