feat(dees-appui-tabs): improve horizontal tabs UX with scroll fades, hover scrollbar, and smooth scroll-to-selected

changelog.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## 2025-12-30 - 3.11.0 - feat(dees-appui-tabs)
+improve horizontal tabs UX with scroll fades, hover scrollbar, and smooth scroll-to-selected
+
+- Add reactive scroll state (canScrollLeft / canScrollRight) and updateScrollState to track horizontal overflow.
+- Introduce scroll-fade gradient elements and CSS to indicate overflow on left/right edges.
+- Show a thin, styled scrollbar on hover (webkit + Firefox styling) instead of hiding it completely.
+- Auto-scroll selected tab into view using scrollTabIntoView and smooth scroll when selecting a tab.
+- Set up a ResizeObserver to recompute scroll state on container size changes and clean it up on disconnect.
+- Ensure lifecycle hooks call updateScrollState (firstUpdated/updated) so indicators stay in sync after render/fonts ready.
+
 ## 2025-12-29 - 3.10.0 - feat(appui-tabs)
 add closeable tabs and auto-hide behavior for content tabs, plus API and events to control them
 

ts_web/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@design.estate/dees-catalog',
-  version: '3.10.0',
+  version: '3.11.0',
   description: 'A comprehensive library that provides dynamic web components for building sophisticated and modern web applications using JavaScript and TypeScript.'
 }

ts_web/elements/00group-appui/dees-appui-tabs/dees-appui-tabs.ts

@@ -4,6 +4,7 @@ import {
   DeesElement,
   type TemplateResult,
   property,
+  state,
   customElement,
   html,
   css,
@@ -39,6 +40,15 @@ export class DeesAppuiTabs extends DeesElement {
   @property({ type: Number })
   accessor autoHideThreshold: number = 0;
 
+  // Scroll state for fade indicators
+  @state()
+  private accessor canScrollLeft: boolean = false;
+
+  @state()
+  private accessor canScrollRight: boolean = false;
+
+  private resizeObserver: ResizeObserver | null = null;
+
   public static styles = [
     themeDefaultStyles,
     cssManager.defaultStyles,
@@ -48,21 +58,56 @@ export class DeesAppuiTabs extends DeesElement {
         display: block;
         position: relative;
         width: 100%;
+        min-width: 0;
+        overflow: hidden;
       }
 
       .tabs-wrapper {
         position: relative;
+        min-width: 0;
       }
 
       .tabs-wrapper.horizontal-wrapper {
         height: 48px;
         border-bottom: 1px solid ${cssManager.bdTheme('#e5e7eb', '#27272a')};
         box-sizing: border-box;
+        overflow: hidden;
+      }
+
+      /* Scroll fade indicators */
+      .scroll-fade {
+        position: absolute;
+        top: 0;
+        bottom: 1px;
+        width: 48px;
+        pointer-events: none;
+        opacity: 0;
+        transition: opacity 0.2s ease;
+        z-index: 10;
+      }
+
+      .scroll-fade-left {
+        left: 0;
+        background: linear-gradient(to right,
+          ${cssManager.bdTheme('#ffffff', '#161616')} 0%,
+          ${cssManager.bdTheme('rgba(255,255,255,0)', 'rgba(22,22,22,0)')} 100%);
+      }
+
+      .scroll-fade-right {
+        right: 0;
+        background: linear-gradient(to left,
+          ${cssManager.bdTheme('#ffffff', '#161616')} 0%,
+          ${cssManager.bdTheme('rgba(255,255,255,0)', 'rgba(22,22,22,0)')} 100%);
+      }
+
+      .scroll-fade.visible {
+        opacity: 1;
       }
 
       .tabsContainer {
         position: relative;
         user-select: none;
+        min-width: 0;
       }
 
       .tabsContainer.horizontal {
@@ -70,14 +115,39 @@ export class DeesAppuiTabs extends DeesElement {
         align-items: center;
         font-size: 14px;
         overflow-x: auto;
-        scrollbar-width: none;
+        overflow-y: hidden;
+        scrollbar-width: thin;
+        scrollbar-color: transparent transparent;
         height: 100%;
         padding: 0 16px;
         gap: 4px;
       }
 
+      /* Show scrollbar on hover */
+      .tabs-wrapper:hover .tabsContainer.horizontal {
+        scrollbar-color: ${cssManager.bdTheme('rgba(0,0,0,0.2)', 'rgba(255,255,255,0.2)')} transparent;
+      }
+
       .tabsContainer.horizontal::-webkit-scrollbar {
-        display: none;
+        height: 4px;
+      }
+
+      .tabsContainer.horizontal::-webkit-scrollbar-track {
+        background: transparent;
+      }
+
+      .tabsContainer.horizontal::-webkit-scrollbar-thumb {
+        background: transparent;
+        border-radius: 2px;
+        transition: background 0.2s ease;
+      }
+
+      .tabs-wrapper:hover .tabsContainer.horizontal::-webkit-scrollbar-thumb {
+        background: ${cssManager.bdTheme('rgba(0,0,0,0.2)', 'rgba(255,255,255,0.2)')};
+      }
+
+      .tabs-wrapper:hover .tabsContainer.horizontal::-webkit-scrollbar-thumb:hover {
+        background: ${cssManager.bdTheme('rgba(0,0,0,0.35)', 'rgba(255,255,255,0.35)')};
       }
 
       .tabsContainer.vertical {
@@ -258,6 +328,19 @@ export class DeesAppuiTabs extends DeesElement {
     const wrapperClass = isHorizontal ? 'tabs-wrapper horizontal-wrapper' : 'vertical-wrapper';
     const containerClass = `tabsContainer ${this.tabStyle}`;
 
+    if (isHorizontal) {
+      return html`
+        <div class="${wrapperClass}">
+          <div class="scroll-fade scroll-fade-left ${this.canScrollLeft ? 'visible' : ''}"></div>
+          <div class="${containerClass}" @scroll=${this.handleScroll}>
+            ${this.tabs.map(tab => this.renderTab(tab, isHorizontal))}
+          </div>
+          <div class="scroll-fade scroll-fade-right ${this.canScrollRight ? 'visible' : ''}"></div>
+          ${this.showTabIndicator ? html`<div class="tabIndicator"></div>` : ''}
+        </div>
+      `;
+    }
+
     return html`
       <div class="${wrapperClass}">
         <div class="${containerClass}">
@@ -308,6 +391,11 @@ export class DeesAppuiTabs extends DeesElement {
     this.selectedTab = tabArg;
     tabArg.action();
 
+    // Scroll selected tab into view
+    requestAnimationFrame(() => {
+      this.scrollTabIntoView(tabArg);
+    });
+
     // Emit tab-select event
     this.dispatchEvent(new CustomEvent('tab-select', {
       detail: { tab: tabArg },
@@ -336,6 +424,78 @@ export class DeesAppuiTabs extends DeesElement {
     if (this.tabs && this.tabs.length > 0) {
       this.selectTab(this.tabs[0]);
     }
+
+    // Set up ResizeObserver for scroll state updates
+    this.setupResizeObserver();
+
+    // Initial scroll state check
+    requestAnimationFrame(() => {
+      this.updateScrollState();
+    });
+  }
+
+  async disconnectedCallback() {
+    await super.disconnectedCallback();
+    if (this.resizeObserver) {
+      this.resizeObserver.disconnect();
+      this.resizeObserver = null;
+    }
+  }
+
+  private setupResizeObserver() {
+    if (this.tabStyle !== 'horizontal') return;
+
+    this.resizeObserver = new ResizeObserver(() => {
+      this.updateScrollState();
+    });
+
+    const container = this.shadowRoot?.querySelector('.tabsContainer.horizontal');
+    if (container) {
+      this.resizeObserver.observe(container);
+    }
+  }
+
+  private handleScroll = () => {
+    this.updateScrollState();
+  };
+
+  private updateScrollState() {
+    const container = this.shadowRoot?.querySelector('.tabsContainer.horizontal') as HTMLElement;
+    if (!container) return;
+
+    const scrollLeft = container.scrollLeft;
+    const scrollWidth = container.scrollWidth;
+    const clientWidth = container.clientWidth;
+
+    // Small threshold to account for rounding
+    const threshold = 2;
+
+    this.canScrollLeft = scrollLeft > threshold;
+    this.canScrollRight = scrollLeft < scrollWidth - clientWidth - threshold;
+  }
+
+  private scrollTabIntoView(tab: interfaces.IMenuItem) {
+    if (this.tabStyle !== 'horizontal') return;
+
+    const tabIndex = this.tabs.indexOf(tab);
+    if (tabIndex === -1) return;
+
+    const container = this.shadowRoot?.querySelector('.tabsContainer.horizontal') as HTMLElement;
+    const tabElement = container?.querySelector(`.tab:nth-child(${tabIndex + 1})`) as HTMLElement;
+
+    if (tabElement && container) {
+      const containerRect = container.getBoundingClientRect();
+      const tabRect = tabElement.getBoundingClientRect();
+
+      // Check if tab is fully visible
+      const isFullyVisible =
+        tabRect.left >= containerRect.left &&
+        tabRect.right <= containerRect.right;
+
+      if (!isFullyVisible) {
+        tabElement.scrollIntoView({ behavior: 'smooth', block: 'nearest', inline: 'nearest' });
+      }
+    }
   }
 
   async updated(changedProperties: Map<string, any>) {
@@ -353,6 +513,7 @@ export class DeesAppuiTabs extends DeesElement {
       }
       requestAnimationFrame(() => {
         this.updateTabIndicator();
+        this.updateScrollState();
       });
     }
   }