fix(ivy): ngOnChanges only runs for binding updates (#27965)

PR Close #27965

packages/core/src/change_detection/change_detection.ts

@@ -11,8 +11,7 @@ import {DefaultKeyValueDifferFactory} from './differs/default_keyvalue_differ';
 import {IterableDifferFactory, IterableDiffers} from './differs/iterable_differs';
 import {KeyValueDifferFactory, KeyValueDiffers} from './differs/keyvalue_differs';
 
-export {SimpleChanges} from '../metadata/lifecycle_hooks';
-export {SimpleChange, WrappedValue, devModeEqual} from './change_detection_util';
+export {WrappedValue, devModeEqual} from './change_detection_util';
 export {ChangeDetectorRef} from './change_detector_ref';
 export {ChangeDetectionStrategy, ChangeDetectorStatus, isDefaultChangeDetectionStrategy} from './constants';
 export {DefaultIterableDifferFactory} from './differs/default_iterable_differ';
@@ -21,6 +20,7 @@ export {DefaultKeyValueDifferFactory} from './differs/default_keyvalue_differ';
 export {CollectionChangeRecord, IterableChangeRecord, IterableChanges, IterableDiffer, IterableDifferFactory, IterableDiffers, NgIterable, TrackByFunction} from './differs/iterable_differs';
 export {KeyValueChangeRecord, KeyValueChanges, KeyValueDiffer, KeyValueDifferFactory, KeyValueDiffers} from './differs/keyvalue_differs';
 export {PipeTransform} from './pipe_transform';
+export {SimpleChange, SimpleChanges} from './simple_change';
 
 
 

packages/core/src/change_detection/change_detection_util.ts

@@ -64,20 +64,6 @@ export class WrappedValue {
   static isWrapped(value: any): value is WrappedValue { return value instanceof WrappedValue; }
 }
 
-/**
- * Represents a basic change from a previous to a new value.
- *
- * @publicApi
- */
-export class SimpleChange {
-  constructor(public previousValue: any, public currentValue: any, public firstChange: boolean) {}
-
-  /**
-   * Check whether the new value is the first value assigned.
-   */
-  isFirstChange(): boolean { return this.firstChange; }
-}
-
 export function isListLikeIterable(obj: any): boolean {
   if (!isJsObject(obj)) return false;
   return Array.isArray(obj) ||

packages/core/src/change_detection/simple_change.ts

@@ -0,0 +1,35 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/**
+ * Represents a basic change from a previous to a new value for a single
+ * property on a directive instance. Passed as a value in a
+ * {@link SimpleChanges} object to the `ngOnChanges` hook.
+ *
+ * @see `OnChanges`
+ *
+ * @publicApi
+ */
+export class SimpleChange {
+  constructor(public previousValue: any, public currentValue: any, public firstChange: boolean) {}
+  /**
+   * Check whether the new value is the first value assigned.
+   */
+  isFirstChange(): boolean { return this.firstChange; }
+}
+
+/**
+ * A hashtable of changes represented by {@link SimpleChange} objects stored
+ * at the declared property name they belong to on a Directive or Component. This is
+ * the type passed to the `ngOnChanges` hook.
+ *
+ * @see `OnChanges`
+ *
+ * @publicApi
+ */
+export interface SimpleChanges { [propName: string]: SimpleChange; }