added null option to Selector

packages/core/src/collection/collection.persistent.ts

@@ -156,7 +156,7 @@ export class CollectionPersistent<
 
             // If successfully loaded Item value, assign Item to Collection
             if (loadedPersistedValueIntoItem)
-              this.collection().assignItem(dummyItem); // TODO SECOND GROUP REBUILD (by calling rebuildGroupThatInclude() in the assignItem() method)
+              this.collection().assignItem(dummyItem, { overwrite: false }); // TODO SECOND GROUP REBUILD (by calling rebuildGroupThatInclude() in the assignItem() method)
           }
         }
       }

packages/core/src/collection/index.ts

@@ -193,7 +193,7 @@ export class Collection<DataType extends Object = DefaultItem> {
    * @param config - Configuration object
    */
   public Selector(
-    initialKey: ItemKey,
+    initialKey: ItemKey | null,
     config: SelectorConfigInterface = {}
   ): Selector<DataType> {
     if (this.isInstantiated) {
@@ -489,7 +489,7 @@ export class Collection<DataType extends Object = DefaultItem> {
    * @param config - Configuration object
    */
   public getGroup(
-    groupKey: GroupKey | undefined,
+    groupKey: GroupKey | undefined | null,
     config: HasConfigInterface = {}
   ): Group<DataType> | undefined {
     config = defineConfig(config, {
@@ -589,7 +589,7 @@ export class Collection<DataType extends Object = DefaultItem> {
    */
   public createSelector(
     selectorKey: SelectorKey,
-    itemKey: ItemKey
+    itemKey: ItemKey | null
   ): Selector<DataType> {
     let selector = this.getSelector(selectorKey, { notExisting: true });
     if (!this.isInstantiated) LogCodeManager.log('1B:02:04');
@@ -662,7 +662,7 @@ export class Collection<DataType extends Object = DefaultItem> {
    * @param config - Configuration object
    */
   public getSelector(
-    selectorKey: SelectorKey | undefined,
+    selectorKey: SelectorKey | undefined | null,
     config: HasConfigInterface = {}
   ): Selector<DataType> | undefined {
     config = defineConfig(config, {
@@ -699,14 +699,10 @@ export class Collection<DataType extends Object = DefaultItem> {
 
     // Create dummy Selector to hold reference
     if (selector == null) {
-      selector = new Selector<DataType>(
-        this,
-        Selector.unknownItemPlaceholderKey,
-        {
-          key: selectorKey,
-          isPlaceholder: true,
-        }
-      );
+      selector = new Selector<DataType>(this, null, {
+        key: selectorKey,
+        isPlaceholder: true,
+      });
       this.selectors[selectorKey] = selector;
     }
 
@@ -773,7 +769,7 @@ export class Collection<DataType extends Object = DefaultItem> {
    * @param config - Configuration object
    */
   public getItem(
-    itemKey: ItemKey | undefined,
+    itemKey: ItemKey | undefined | null,
     config: HasConfigInterface = {}
   ): Item<DataType> | undefined {
     config = defineConfig(config, {
@@ -1425,9 +1421,11 @@ export class Collection<DataType extends Object = DefaultItem> {
     }
 
     // Check if Item already exists
-    if (this.getItem(itemKey) != null) {
-      if (!config.overwrite) return true;
-      else increaseCollectionSize = false;
+    if (this.getItem(itemKey, { notExisting: true }) != null) {
+      if (!config.overwrite) {
+        this.assignData(item._value);
+        return true;
+      } else increaseCollectionSize = false;
     }
 
     // Assign/add Item to Collection

packages/core/src/collection/selector.ts

@@ -8,20 +8,19 @@ import {
   StateRuntimeJobConfigInterface,
 } from '../internal';
 
-export class Selector<DataType extends Object = DefaultItem> extends State<
-  DataType | undefined
-> {
+export class Selector<
+  DataType extends Object = DefaultItem
+> extends State<DataType | null> {
   // Collection the Selector belongs to
   public collection: () => Collection<DataType>;
 
-  static unknownItemPlaceholderKey = '__UNKNOWN__ITEM__KEY__';
   static rebuildSelectorSideEffectKey = 'rebuildSelector';
   static rebuildItemSideEffectKey = 'rebuildItem';
 
   // Item the Selector represents
-  public _item: Item<DataType> | undefined;
+  public _item: Item<DataType> | null;
   // Key/Name identifier of the Item the Selector represents
-  public _itemKey: ItemKey;
+  public _itemKey: ItemKey | null;
 
   /**
    * A Selector represents an Item from a Collection in the long term.
@@ -39,23 +38,21 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
    */
   constructor(
     collection: Collection<DataType>,
-    itemKey: ItemKey,
+    itemKey: ItemKey | null,
     config: SelectorConfigInterface = {}
   ) {
     config = defineConfig(config, {
       isPlaceholder: false,
     });
-    super(collection.agileInstance(), undefined, config);
+    super(collection.agileInstance(), null, config);
     this.collection = () => collection;
-    this._item = undefined;
-    this._itemKey = !config.isPlaceholder
-      ? itemKey
-      : Selector.unknownItemPlaceholderKey;
+    this._item = null;
+    this._itemKey = !config.isPlaceholder && itemKey != null ? itemKey : null;
     this._key = config?.key;
     this.isPlaceholder = true; // Because hasn't selected any Item yet
 
     // Initial select of the Item
-    if (!config.isPlaceholder) this.select(itemKey, { overwrite: true });
+    if (this._itemKey != null) this.select(itemKey, { overwrite: true });
   }
 
   /**
@@ -65,7 +62,7 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
    *
    * @public
    */
-  public get itemKey(): ItemKey {
+  public get itemKey(): ItemKey | null {
     return this._itemKey;
   }
 
@@ -78,7 +75,7 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
    * @public
    * @param value - New key/name identifier of the Item to be represented by the Selector.
    */
-  public set itemKey(value: ItemKey) {
+  public set itemKey(value: ItemKey | null) {
     this.select(value);
   }
 
@@ -89,7 +86,7 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
    *
    * @public
    */
-  public get item(): Item<DataType> | undefined {
+  public get item(): Item<DataType> | null {
     return this._item;
   }
 
@@ -102,7 +99,7 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
    * @public
    * @param value - New Item to be represented by the Selector.
    */
-  public set item(value: Item<DataType> | undefined) {
+  public set item(value: Item<DataType> | null) {
     if (value?._key) this.select(value._key);
   }
 
@@ -116,7 +113,7 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
    * @param config - Configuration object
    */
   public select(
-    itemKey: ItemKey,
+    itemKey: ItemKey | null,
     config: StateRuntimeJobConfigInterface = {}
   ): this {
     config = defineConfig(config, {
@@ -140,7 +137,9 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
       return this;
 
     // Unselect old Item
-    this.unselect({ background: true });
+    this.unselect({ background: itemKey != null });
+
+    if (itemKey == null) return this;
 
     // Retrieve new Item from Collection
     const newItem = this.collection().getItemWithReference(itemKey);
@@ -224,16 +223,20 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
     });
 
     // Unselect Item
-    if (item) {
+    if (item != null) {
       item.selectedBy.delete(this._key as any);
       item.removeSideEffect(Selector.rebuildSelectorSideEffectKey);
       item.removeSideEffect(Selector.rebuildItemSideEffectKey);
-      if (item.isPlaceholder) delete this.collection().data[this._itemKey];
+      if (
+        item.isPlaceholder &&
+        this._itemKey != null
+      )
+        delete this.collection().data[this._itemKey];
     }
 
     // Reset Selector
-    this._item = undefined;
-    this._itemKey = Selector.unknownItemPlaceholderKey;
+    this._item = null;
+    this._itemKey = null;
     this.rebuildSelector(config);
     this.isPlaceholder = true;
 
@@ -250,7 +253,10 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
    * @param itemKey - Key/Name identifier of the Item.
    * @param correctlySelected - Whether the Item has to be selected correctly.
    */
-  public hasSelected(itemKey: ItemKey, correctlySelected = true): boolean {
+  public hasSelected(
+    itemKey: ItemKey | null,
+    correctlySelected = true
+  ): boolean {
     if (correctlySelected) {
       return (
         this._itemKey === itemKey &&
@@ -273,7 +279,7 @@ export class Selector<DataType extends Object = DefaultItem> extends State<
   public rebuildSelector(config: StateRuntimeJobConfigInterface = {}): this {
     // Assign 'undefined' to the Selector value if no Item is set
     if (this._item == null || this._item.isPlaceholder) {
-      this.set(undefined, config);
+      this.set(null, config);
       return this;
     }
 

packages/core/tests/unit/collection/collection.persistent.test.ts

@@ -414,9 +414,9 @@ describe('CollectionPersistent Tests', () => {
               followCollectionPersistKeyPattern: false,
             }
           );
-          expect(dummyCollection.assignItem).toHaveBeenCalledWith(
-            placeholderItem1
-          );
+          expect(
+            dummyCollection.assignItem
+          ).toHaveBeenCalledWith(placeholderItem1, { overwrite: false });
           expect(dummyCollection.assignItem).not.toHaveBeenCalledWith(
             placeholderItem2
           ); // Because Item persistent isn't ready
@@ -507,9 +507,9 @@ describe('CollectionPersistent Tests', () => {
               followCollectionPersistKeyPattern: false,
             }
           );
-          expect(dummyCollection.assignItem).toHaveBeenCalledWith(
-            placeholderItem1
-          );
+          expect(
+            dummyCollection.assignItem
+          ).toHaveBeenCalledWith(placeholderItem1, { overwrite: false });
           expect(dummyCollection.assignItem).not.toHaveBeenCalledWith(
             placeholderItem3
           ); // Because Item 3 is already present in the Collection

packages/core/tests/unit/collection/collection.test.ts

@@ -1414,7 +1414,10 @@ describe('Collection Tests', () => {
 
         expect(response).toBeInstanceOf(Selector);
         expect(response.isPlaceholder).toBeTruthy();
+        expect(response._item).toBeNull();
+        expect(response._itemKey).toBeNull();
         expect(response._key).toBe('notExistingSelector');
+
         expect(collection.selectors['notExistingSelector']).toBe(response);
         expect(ComputedTracker.tracked).toHaveBeenCalledWith(response.observer);
       });
@@ -2832,6 +2835,7 @@ describe('Collection Tests', () => {
         dummyItem1.patch = jest.fn();
         toAddDummyItem2.patch = jest.fn();
         collection.rebuildGroupsThatIncludeItemKey = jest.fn();
+        collection.assignData = jest.fn();
       });
 
       it('should assign valid Item to Collection (default config)', () => {
@@ -2847,6 +2851,7 @@ describe('Collection Tests', () => {
             background: false,
           }
         );
+        expect(collection.assignData).not.toHaveBeenCalled();
 
         expect(toAddDummyItem2.patch).not.toHaveBeenCalled();
         expect(toAddDummyItem2._key).toBe('dummyItem2');
@@ -2870,6 +2875,7 @@ describe('Collection Tests', () => {
             background: true,
           }
         );
+        expect(collection.assignData).not.toHaveBeenCalled();
 
         expect(toAddDummyItem2.patch).not.toHaveBeenCalled();
         expect(toAddDummyItem2._key).toBe('dummyItem2');
@@ -2895,6 +2901,7 @@ describe('Collection Tests', () => {
             background: false,
           }
         );
+        expect(collection.assignData).not.toHaveBeenCalled();
 
         expect(toAddDummyItem2.patch).toHaveBeenCalledWith(
           { id: 'randomDummyId' },
@@ -2923,6 +2930,7 @@ describe('Collection Tests', () => {
         expect(
           collection.rebuildGroupsThatIncludeItemKey
         ).not.toHaveBeenCalled();
+        expect(collection.assignData).not.toHaveBeenCalled();
 
         expect(toAddDummyItem2.patch).not.toHaveBeenCalled();
         expect(toAddDummyItem2._key).toBe('dummyItem2');
@@ -2944,6 +2952,7 @@ describe('Collection Tests', () => {
         expect(
           collection.rebuildGroupsThatIncludeItemKey
         ).not.toHaveBeenCalled();
+        expect(collection.assignData).toHaveBeenCalledWith(dummyItem1._value);
 
         expect(dummyItem1.patch).not.toHaveBeenCalled();
         expect(dummyItem1._key).toBe('dummyItem1');
@@ -2965,6 +2974,7 @@ describe('Collection Tests', () => {
             background: false,
           }
         );
+        expect(collection.assignData).not.toHaveBeenCalled();
 
         expect(dummyItem1.patch).not.toHaveBeenCalled();
         expect(dummyItem1._key).toBe('dummyItem1');