From b39efdd9d65953fe690794eb4f85a199600ff3a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ingo=20B=C3=BCrk?= <ingo.buerk@tngtech.com>
Date: Sat, 24 Nov 2018 16:00:13 +0100
Subject: [PATCH] fix(common): KeyValuePipe should return empty array for empty
 objects (#27258)

This lets KeyValuePipe return an empty array (rather than undefined)
when the input is empty.

PR Close #27258
---
 packages/common/src/pipes/keyvalue_pipe.ts       | 4 +---
 packages/common/test/pipes/keyvalue_pipe_spec.ts | 8 ++++++++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/packages/common/src/pipes/keyvalue_pipe.ts b/packages/common/src/pipes/keyvalue_pipe.ts
index ef0eb5f5a6..5770f6a75b 100644
--- a/packages/common/src/pipes/keyvalue_pipe.ts
+++ b/packages/common/src/pipes/keyvalue_pipe.ts
@@ -47,10 +47,8 @@ export interface KeyValue<K, V> {
 export class KeyValuePipe implements PipeTransform {
   constructor(private readonly differs: KeyValueDiffers) {}
 
-  // TODO(issue/24571): remove '!'.
   private differ !: KeyValueDiffer<any, any>;
-  // TODO(issue/24571): remove '!'.
-  private keyValues !: Array<KeyValue<any, any>>;
+  private keyValues: Array<KeyValue<any, any>> = [];
 
   transform<K, V>(input: null, compareFn?: (a: KeyValue<K, V>, b: KeyValue<K, V>) => number): null;
   transform<V>(
diff --git a/packages/common/test/pipes/keyvalue_pipe_spec.ts b/packages/common/test/pipes/keyvalue_pipe_spec.ts
index e9f1c53bfc..5d69e9929a 100644
--- a/packages/common/test/pipes/keyvalue_pipe_spec.ts
+++ b/packages/common/test/pipes/keyvalue_pipe_spec.ts
@@ -25,6 +25,10 @@ describe('KeyValuePipe', () => {
     expect(pipe.transform(fn as any)).toEqual(null);
   });
   describe('object dictionary', () => {
+    it('should return empty array of an empty dictionary', () => {
+      const pipe = new KeyValuePipe(defaultKeyValueDiffers);
+      expect(pipe.transform({})).toEqual([]);
+    });
     it('should transform a basic dictionary', () => {
       const pipe = new KeyValuePipe(defaultKeyValueDiffers);
       expect(pipe.transform({1: 2})).toEqual([{key: '1', value: 2}]);
@@ -62,6 +66,10 @@ describe('KeyValuePipe', () => {
   });
 
   describe('Map', () => {
+    it('should return an empty array for an empty Map', () => {
+      const pipe = new KeyValuePipe(defaultKeyValueDiffers);
+      expect(pipe.transform(new Map())).toEqual([]);
+    });
     it('should transform a basic Map', () => {
       const pipe = new KeyValuePipe(defaultKeyValueDiffers);
       expect(pipe.transform(new Map([[1, 2]]))).toEqual([{key: 1, value: 2}]);