feat: support reverse button collapsing order in menu-bar

packages/menu-bar/src/vaadin-menu-bar-mixin.d.ts

@@ -138,6 +138,13 @@ export declare class MenuBarMixinClass {
    */
   openOnHover: boolean | null | undefined;
 
+  /**
+   * If true, the buttons will be collapsed into the overflow menu
+   * starting from the "start" end of the bar instead of the "end".
+   * @attr {boolean} reverse-collapse
+   */
+  reverseCollapse: boolean | null | undefined;
+
   /**
    * Closes the current submenu.
    */

packages/menu-bar/src/vaadin-menu-bar-mixin.js

@@ -135,6 +135,15 @@ export const MenuBarMixin = (superClass) =>
           type: Boolean,
         },
 
+        /**
+         * If true, the buttons will be collapsed into the overflow menu
+         * starting from the "start" end of the bar instead of the "end".
+         * @attr {boolean} reverse-collapse
+         */
+        reverseCollapse: {
+          type: Boolean,
+        },
+
         /**
          * @type {boolean}
          * @protected
@@ -162,6 +171,7 @@ export const MenuBarMixin = (superClass) =>
         '__hasOverflowChanged(_hasOverflow, _overflow)',
         '__i18nChanged(i18n, _overflow)',
         '_menuItemsChanged(items, _overflow, _container)',
+        '_reverseCollapseChanged(reverseCollapse, _overflow, _container)',
       ];
     }
 
@@ -320,6 +330,15 @@ export const MenuBarMixin = (superClass) =>
       }
     }
 
+    /**
+     * A callback for the 'reverseCollapse' property observer.
+     */
+    _reverseCollapseChanged(_reverseCollapse, overflow, container) {
+      if (overflow && container) {
+        this.__detectOverflow();
+      }
+    }
+
     /** @private */
     __hasOverflowChanged(hasOverflow, overflow) {
       if (overflow) {
@@ -410,34 +429,35 @@ export const MenuBarMixin = (superClass) =>
         const isRTL = this.__isRTL;
         const containerLeft = container.getBoundingClientRect().left;
 
-        let i;
-        for (i = buttons.length; i > 0; i--) {
-          const btn = buttons[i - 1];
-          const btnStyle = getComputedStyle(btn);
-          const btnLeft = btn.getBoundingClientRect().left - containerLeft;
+        const remaining = [...buttons];
+        while (remaining.length) {
+          const lastButton = remaining[remaining.length - 1];
+          const btnLeft = lastButton.getBoundingClientRect().left - containerLeft;
 
           // If this button isn't overflowing, then the rest aren't either
           if (
-            (!isRTL && btnLeft + btn.offsetWidth < container.offsetWidth - overflow.offsetWidth) ||
+            (!isRTL && btnLeft + lastButton.offsetWidth < container.offsetWidth - overflow.offsetWidth) ||
             (isRTL && btnLeft >= overflow.offsetWidth)
           ) {
             break;
           }
 
+          const btn = this.reverseCollapse ? remaining.shift() : remaining.pop();
+
+          // Save width for buttons with component
+          btn.style.width = getComputedStyle(btn).width;
           btn.disabled = true;
           btn.style.visibility = 'hidden';
           btn.style.position = 'absolute';
-          // Save width for buttons with component
-          btn.style.width = btnStyle.width;
         }
-        const items = buttons.filter((_, idx) => idx >= i).map((b) => b.item);
+
+        const items = buttons.filter((b) => !remaining.includes(b)).map((b) => b.item);
         this.__updateOverflow(items);
 
-        const remaining = buttons.slice(0, i);
         // Ensure there is at least one button with tabindex set to 0
         // so that menu-bar is not skipped when navigating with Tab
-        if (i > 0 && !remaining.some((btn) => btn.getAttribute('tabindex') === '0')) {
-          this._setTabindex(remaining[i - 1], true);
+        if (remaining.length && !remaining.some((btn) => btn.getAttribute('tabindex') === '0')) {
+          this._setTabindex(remaining[remaining.length - 1], true);
         }
       }
     }
@@ -461,6 +481,14 @@ export const MenuBarMixin = (superClass) =>
 
       const isSingleButton = newOverflowCount === buttons.length || (newOverflowCount === 0 && buttons.length === 1);
       this.toggleAttribute('has-single-button', isSingleButton);
+
+      // Apply first/last visible attributes to the visible buttons
+      buttons
+        .filter((btn) => btn.style.visibility !== 'hidden')
+        .forEach((btn, index, visibleButtons) => {
+          btn.toggleAttribute('first-visible', index === 0);
+          btn.toggleAttribute('last-visible', !this._hasOverflow && index === visibleButtons.length - 1);
+        });
     }
 
     /** @protected */

packages/menu-bar/test/dom/__snapshots__/menu-bar.test.snap.js

@@ -5,6 +5,7 @@ snapshots["menu-bar basic"] =
 `<vaadin-menu-bar role="menubar">
   <vaadin-menu-bar-button
     class="home"
+    first-visible=""
     role="menuitem"
     tabindex="0"
   >
@@ -28,6 +29,7 @@ snapshots["menu-bar basic"] =
   </vaadin-menu-bar-button>
   <vaadin-menu-bar-button
     class="help"
+    last-visible=""
     role="menuitem"
     tabindex="0"
   >

packages/menu-bar/test/overflow.test.js

@@ -203,6 +203,50 @@ describe('overflow', () => {
       menu.i18n = { ...menu.i18n, moreOptions: '' };
       expect(overflow.hasAttribute('aria-label')).to.be.false;
     });
+
+    describe('reverse-collapse', () => {
+      beforeEach(() => {
+        menu.reverseCollapse = true;
+      });
+
+      it('should show overflow button and hide the buttons which do not fit', () => {
+        assertHidden(buttons[0]);
+        expect(buttons[0].disabled).to.be.true;
+        assertHidden(buttons[1]);
+        expect(buttons[1].disabled).to.be.true;
+        assertHidden(buttons[2]);
+        expect(buttons[2].disabled).to.be.true;
+        assertVisible(buttons[3]);
+        expect(buttons[3].disabled).to.be.false;
+        assertVisible(buttons[4]);
+        expect(buttons[4].disabled).to.be.true;
+
+        expect(overflow.hasAttribute('hidden')).to.be.false;
+      });
+
+      it('should set items to overflow button for buttons which do not fit', () => {
+        expect(overflow.item).to.be.instanceOf(Object);
+        expect(overflow.item.children).to.be.instanceOf(Array);
+        expect(overflow.item.children.length).to.equal(3);
+        expect(overflow.item.children[0]).to.deep.equal(menu.items[0]);
+        expect(overflow.item.children[1]).to.deep.equal(menu.items[1]);
+        expect(overflow.item.children[2]).to.deep.equal(menu.items[2]);
+      });
+
+      it('should update oveflow when reverseCollapse changes', () => {
+        menu.reverseCollapse = false;
+        assertVisible(buttons[0]);
+        expect(buttons[0].disabled).to.be.false;
+        assertVisible(buttons[1]);
+        expect(buttons[1].disabled).to.be.false;
+        assertHidden(buttons[2]);
+        expect(buttons[2].disabled).to.be.true;
+        assertHidden(buttons[3]);
+        expect(buttons[3].disabled).to.be.true;
+        assertHidden(buttons[4]);
+        expect(buttons[4].disabled).to.be.true;
+      });
+    });
   });
 
   describe('has-single-button attribute', () => {

packages/menu-bar/test/visual/lumo/menu-bar.test.js

@@ -44,6 +44,16 @@ describe('menu-bar', () => {
           await nextRender(element);
           await visualDiff(document.body, `${dir}-opened`);
         });
+
+        it('reverse-collapse opened', async () => {
+          div.style.width = '250px';
+          element.reverseCollapse = true;
+          await nextRender(element);
+          element._buttons[4].click();
+          const overlay = element._subMenu._overlayElement;
+          await oneEvent(overlay, 'vaadin-overlay-open');
+          await visualDiff(document.body, `${dir}-reverse-collapse-opened`);
+        });
       });
 
       describe('single button', () => {

packages/menu-bar/test/visual/material/menu-bar.test.js

@@ -44,6 +44,17 @@ describe('menu-bar', () => {
           await nextRender(element);
           await visualDiff(document.body, `${dir}-opened`);
         });
+
+        it('reverse-collapse opened', async () => {
+          div.style.width = '250px';
+          element.reverseCollapse = true;
+          element.setAttribute('theme', 'outlined');
+          await nextRender(element);
+          element._buttons[4].click();
+          const overlay = element._subMenu._overlayElement;
+          await oneEvent(overlay, 'vaadin-overlay-open');
+          await visualDiff(document.body, `${dir}-reverse-collapse-opened`);
+        });
       });
 
       describe('single button', () => {

packages/menu-bar/theme/lumo/vaadin-menu-bar-button-styles.js

@@ -46,14 +46,14 @@ const menuBarButton = css`
     padding: 0;
   }
 
-  :host(:first-of-type) {
+  :host([first-visible]) {
     border-radius: var(--lumo-border-radius-m) 0 0 var(--lumo-border-radius-m);
 
     /* Needed to retain the focus-ring with border-radius */
     margin-left: calc(var(--lumo-space-xs) / 2);
   }
 
-  :host(:nth-last-of-type(2)),
+  :host([last-visible]),
   :host([slot='overflow']) {
     border-radius: 0 var(--lumo-border-radius-m) var(--lumo-border-radius-m) 0;
   }
@@ -86,12 +86,12 @@ const menuBarButton = css`
     border-radius: 0;
   }
 
-  :host([dir='rtl']:first-of-type) {
+  :host([dir='rtl'][first-visible]) {
     border-radius: 0 var(--lumo-border-radius-m) var(--lumo-border-radius-m) 0;
     margin-right: calc(var(--lumo-space-xs) / 2);
   }
 
-  :host([dir='rtl']:nth-last-of-type(2)),
+  :host([dir='rtl'][last-visible]),
   :host([dir='rtl'][slot='overflow']) {
     border-radius: var(--lumo-border-radius-m) 0 0 var(--lumo-border-radius-m);
   }

packages/menu-bar/theme/lumo/vaadin-menu-bar-styles.js

@@ -8,7 +8,7 @@ registerStyles(
       border-radius: var(--lumo-border-radius-m);
     }
 
-    :host([theme~='end-aligned']) ::slotted(vaadin-menu-bar-button:first-of-type),
+    :host([theme~='end-aligned']) ::slotted(vaadin-menu-bar-button[first-visible]),
     :host([theme~='end-aligned'][has-single-button]) ::slotted(vaadin-menu-bar-button) {
       margin-inline-start: auto;
     }

packages/menu-bar/theme/material/vaadin-menu-bar-button-styles.js

@@ -49,11 +49,11 @@ const menuBarButton = css`
     margin-right: 1px;
   }
 
-  :host(:first-of-type) {
+  :host([first-visible]) {
     border-radius: 4px 0 0 4px;
   }
 
-  :host(:nth-last-of-type(2)),
+  :host([last-visible]),
   :host([slot='overflow']) {
     border-radius: 0 4px 4px 0;
   }
@@ -72,7 +72,7 @@ const menuBarButton = css`
     margin-right: -1px;
   }
 
-  :host([theme~='outlined']:not([dir='rtl']):nth-last-of-type(2)),
+  :host([theme~='outlined']:not([dir='rtl'])[last-visible]),
   :host([theme~='outlined']:not([dir='rtl'])[slot='overflow']) {
     margin-right: 0;
   }
@@ -83,11 +83,11 @@ const menuBarButton = css`
   }
 
   /* RTL styles */
-  :host([dir='rtl']:first-of-type) {
+  :host([dir='rtl'][first-visible]) {
     border-radius: 0 4px 4px 0;
   }
 
-  :host([dir='rtl']:nth-last-of-type(2)),
+  :host([dir='rtl'][last-visible]),
   :host([dir='rtl'][slot='overflow']) {
     border-radius: 4px 0 0 4px;
   }
@@ -100,7 +100,7 @@ const menuBarButton = css`
     margin-left: -1px;
   }
 
-  :host([theme~='outlined'][dir='rtl']:nth-last-of-type(2)),
+  :host([theme~='outlined'][dir='rtl'][last-visible]),
   :host([theme~='outlined'][dir='rtl'][slot='overflow']) {
     margin-left: 0;
   }

packages/menu-bar/theme/material/vaadin-menu-bar-styles.js

@@ -12,7 +12,7 @@ registerStyles(
       border-radius: 4px;
     }
 
-    :host([theme~='end-aligned']) ::slotted(vaadin-menu-bar-button:first-of-type),
+    :host([theme~='end-aligned']) ::slotted(vaadin-menu-bar-button[first-visible]),
     :host([theme~='end-aligned'][has-single-button]) ::slotted(vaadin-menu-bar-button) {
       margin-inline-start: auto;
     }