fix(cdk-experimental/ui-patterns): enter/space/click in single selection mode should not deselect tree item (#31843)

Author: ok7sai

src/cdk-experimental/ui-patterns/tree/tree.spec.ts

@@ -501,19 +501,33 @@ describe('Tree Pattern', () => {
 
         tree.onKeydown(space());
         expect(tree.inputs.value()).toEqual(['Item 0']);
+      });
+
+      it('should not deselect an item on Space', () => {
+        const {tree} = createTree(treeExample, treeInputs);
 
         tree.onKeydown(space());
-        expect(tree.inputs.value()).toEqual([]);
+        expect(tree.inputs.value()).toEqual(['Item 0']);
+
+        tree.onKeydown(space());
+        expect(tree.inputs.value()).toEqual(['Item 0']);
       });
 
       it('should select an item on Enter', () => {
         const {tree} = createTree(treeExample, treeInputs);
 
         tree.onKeydown(enter());
         expect(tree.inputs.value()).toEqual(['Item 0']);
+      });
+
+      it('should not deselect an item on Enter', () => {
+        const {tree} = createTree(treeExample, treeInputs);
 
         tree.onKeydown(enter());
-        expect(tree.inputs.value()).toEqual([]);
+        expect(tree.inputs.value()).toEqual(['Item 0']);
+
+        tree.onKeydown(enter());
+        expect(tree.inputs.value()).toEqual(['Item 0']);
       });
 
       it('should only allow one selected item', () => {
@@ -919,10 +933,19 @@ describe('Tree Pattern', () => {
         tree.onPointerdown(createClickEvent(item1.element()));
         expect(tree.activeItem()).toBe(item1);
         expect(tree.inputs.value()).toEqual(['Item 1']);
+      });
+
+      it('should not deselect item on click', () => {
+        const {tree, allItems} = createTree(treeExample, treeInputs);
+        const item1 = getItemByValue(allItems(), 'Item 1');
 
         tree.onPointerdown(createClickEvent(item1.element()));
         expect(tree.activeItem()).toBe(item1);
-        expect(tree.inputs.value()).toEqual([]);
+        expect(tree.inputs.value()).toEqual(['Item 1']);
+
+        tree.onPointerdown(createClickEvent(item1.element()));
+        expect(tree.activeItem()).toBe(item1);
+        expect(tree.inputs.value()).toEqual(['Item 1']);
       });
 
       it('should not change selection when the tree is disabled', () => {

src/cdk-experimental/ui-patterns/tree/tree.ts

@@ -244,8 +244,8 @@ export class TreePattern<V> {
     }
 
     if (!this.followFocus() && !this.inputs.multi()) {
-      manager.on(this.dynamicSpaceKey, () => list.toggleOne());
-      manager.on('Enter', () => list.toggleOne());
+      manager.on(this.dynamicSpaceKey, () => list.selectOne());
+      manager.on('Enter', () => list.selectOne());
     }
 
     if (this.inputs.multi() && this.followFocus()) {
@@ -275,14 +275,10 @@ export class TreePattern<V> {
       manager.on(Modifier.Shift, e => this.goto(e, {selectRange: true}));
     }
 
-    if (!this.multi() && this.followFocus()) {
+    if (!this.multi()) {
       return manager.on(e => this.goto(e, {selectOne: true}));
     }
 
-    if (!this.multi() && !this.followFocus()) {
-      return manager.on(e => this.goto(e, {toggle: true}));
-    }
-
     if (this.multi() && this.followFocus()) {
       return manager
         .on(e => this.goto(e, {selectOne: true}))