fix(lib): start selection inbetween select items

This commit fixes the issue of not being able to start a selection if
mousedown occured on neither Host element nor select item element
but inbetween. The issue occurs if `SelectItem`s are not direct children
of the `SelectContainer`.

Fixes d3lm#144

cypress/integration/dragging.spec.ts

@@ -1,7 +1,9 @@
 import { DEFAULT_CONFIG } from '../../projects/ngx-drag-to-select/src/lib/config';
 
 import {
+  disableDragOverItems,
   disableSelection,
+  disableSelectOnClick,
   disableSelectOnDrag,
   enableSelectMode,
   getDesktopExample,
@@ -91,6 +93,78 @@ describe('Dragging', () => {
           .dispatch('mouseup');
       });
     });
+
+    describe('Selection with dragOverItems set to false', () => {
+      it('should not start selection over items', () => {
+        disableDragOverItems().then(() => {
+          getDesktopExample().within(() => {
+            cy.getSelectItem(0)
+              .dispatch('mousedown', { button: 0 })
+              .getSelectItem(6, 'end')
+              .dispatch('mousemove')
+              .shouldSelect([1])
+              .getSelectBox()
+              .then(shouldBeInvisible)
+              .get('@end')
+              .dispatch('mouseup');
+          });
+        });
+      });
+
+      it('should start selection on element inbetween SelectContainer and SelectItem', () => {
+        disableDragOverItems().then(() => {
+          getDesktopExample().within(() => {
+            cy.get('mat-grid-list')
+              .as('end')
+              .scrollIntoView()
+              .trigger('mousedown', 210, 50, { button: 0 })
+              .getSelectItem(6)
+              .dispatch('mousemove')
+              .shouldSelect([2, 3, 6, 7])
+              .getSelectBox()
+              .then(shouldBeVisible)
+              .get('@end')
+              .dispatch('mouseup');
+          });
+        });
+      });
+    });
+
+    describe('Selection with selectOnClick set to false', () => {
+      it('should not start selection over items', () => {
+        disableSelectOnClick().then(() => {
+          getDesktopExample().within(() => {
+            cy.getSelectItem(0)
+              .dispatch('mousedown', { button: 0 })
+              .getSelectItem(6, 'end')
+              .dispatch('mousemove')
+              .shouldSelect([])
+              .getSelectBox()
+              .then(shouldBeInvisible)
+              .get('@end')
+              .dispatch('mouseup');
+          });
+        });
+      });
+
+      it('should start selection on element inbetween SelectContainer and SelectItem', () => {
+        disableSelectOnClick().then(() => {
+          getDesktopExample().within(() => {
+            cy.get('mat-grid-list')
+              .as('end')
+              .scrollIntoView()
+              .trigger('mousedown', 210, 50, { button: 0 })
+              .getSelectItem(6)
+              .dispatch('mousemove')
+              .shouldSelect([2, 3, 6, 7])
+              .getSelectBox()
+              .then(shouldBeVisible)
+              .get('@end')
+              .dispatch('mouseup');
+          });
+        });
+      });
+    });
   });
 
   describe('Keyboard Events', () => {

cypress/support/utils.ts

@@ -52,6 +52,10 @@ export const disableSelectOnDrag = () => {
   return cy.get('[data-cy="selectOnDrag"]').click();
 };
 
+export const disableDragOverItems = () => {
+  return cy.get('[data-cy="dragOverItems"]').click();
+};
+
 export const disableSelectOnClick = () => {
   return cy.get('[data-cy="selectOnClick"]').click();
 };

projects/ngx-drag-to-select/src/lib/select-container.component.ts

@@ -122,6 +122,7 @@ export class SelectContainerComponent implements AfterViewInit, OnDestroy, After
 
   private _selectedItems$ = new BehaviorSubject<Array<any>>([]);
   private _selectableItems: Array<SelectItemDirective> = [];
+  private _selectableItemsNative: Array<HTMLElement> = [];
   private updateItems$ = new Subject<UpdateAction>();
   private destroy$ = new Subject<void>();
 
@@ -163,7 +164,7 @@ export class SelectContainerComponent implements AfterViewInit, OnDestroy, After
       const mousedown$ = fromEvent<MouseEvent>(this.host, 'mousedown').pipe(
         filter((event) => event.button === 0), // only emit left mouse
         filter(() => !this.disabled),
-        filter((event) => this.selectOnClick || event.target === this.host),
+        filter((event) => this.selectOnClick || this._isClickOutsideSelectableItem(event.target)),
         tap((event) => this._onMouseDown(event)),
         share()
       );
@@ -172,7 +173,7 @@ export class SelectContainerComponent implements AfterViewInit, OnDestroy, After
         filter((event) => !this.shortcuts.disableSelection(event)),
         filter(() => !this.selectMode),
         filter(() => !this.disableDrag),
-        filter((event) => this.dragOverItems || event.target === this.host),
+        filter((event) => this.dragOverItems || this._isClickOutsideSelectableItem(event.target)),
         switchMap(() => mousemove$.pipe(takeUntil(mouseup$))),
         share()
       );
@@ -265,6 +266,7 @@ export class SelectContainerComponent implements AfterViewInit, OnDestroy, After
 
   ngAfterContentInit() {
     this._selectableItems = this.$selectableItems.toArray();
+    this._selectableItemsNative = this._selectableItems.map((directive) => directive.nativeElememnt);
   }
 
   selectAll() {
@@ -351,6 +353,7 @@ export class SelectContainerComponent implements AfterViewInit, OnDestroy, After
       .subscribe(([items, selectedItems]: [QueryList<SelectItemDirective>, any[]]) => {
         const newList = items.toArray();
         this._selectableItems = newList;
+        this._selectableItemsNative = this._selectableItems.map((directive) => directive.nativeElememnt);
         const newValues = newList.map((item) => item.value);
         const removedItems = selectedItems.filter((item) => !newValues.includes(item));
 
@@ -680,4 +683,20 @@ export class SelectContainerComponent implements AfterViewInit, OnDestroy, After
 
     return null;
   }
+
+  private _isClickOutsideSelectableItem(element: EventTarget): boolean {
+    if (!(element instanceof HTMLElement)) {
+      return false;
+    }
+
+    if (element === this.host) {
+      return true;
+    }
+
+    if (this._selectableItemsNative.includes(element)) {
+      return false;
+    }
+
+    return this._isClickOutsideSelectableItem(element.parentElement);
+  }
 }