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    Style: Wireframe

    Components · Overlays

    Tooltip

    A short label on hover and keyboard focus. Stays while hovered, Escape hides it (WCAG 1.4.13).

    Copy the install commandDeploys the main branch to production

    Both previews render the same markup; the HTML tab below is that markup without a framework.

    Install

    React
    npx shadcn@latest add https://www.themes.dev/ui/r/tooltip.json
    Astro
    npx shadcn@latest add https://www.themes.dev/ui/r/astro/tooltip.json

    Or copy the files below into your project. They need clsx, tailwind-merge, and the themes.dev UI theme. The HTML needs only the compiled CSS and the script.

    tooltip.client.ts
    // Tooltip behaviour, shared by the Astro, React and HTML versions. A [data-tooltip] wrapper holds one focusable
    // trigger and a [role=tooltip][popover=manual]. The trigger gets aria-describedby. The tooltip shows 300ms after the
    // pointer enters and at once on keyboard focus; it stays while the pointer is over the trigger or the tooltip itself
    // (WCAG 1.4.13: hoverable), and Escape hides it without moving focus (dismissable).
    declare global {
      interface Window {
        __caseroomTooltip?: boolean;
      }
    }
    
    const anchored = typeof CSS !== 'undefined' && CSS.supports('anchor-name: --a');
    const timers = new WeakMap<HTMLElement, number>();
    const partsOf = (root: HTMLElement) => ({
      tip: root.querySelector<HTMLElement>(':scope > [role=tooltip]'),
      trigger: root.querySelector<HTMLElement>(':scope > :not([role=tooltip])'),
    });
    
    export function wireTooltip(root: HTMLElement) {
      const { tip, trigger } = partsOf(root);
      if (!tip || !trigger) return;
      const focusable = trigger.matches('a[href], button, input, select, textarea, [tabindex]') ? trigger : trigger.querySelector<HTMLElement>('a[href], button, input, select, textarea, [tabindex]');
      const ids = new Set((focusable?.getAttribute('aria-describedby') ?? '').split(/\s+/).filter(Boolean));
      ids.add(tip.id);
      focusable?.setAttribute('aria-describedby', [...ids].join(' '));
    }
    
    function place(tip: HTMLElement, trigger: HTMLElement) {
      if (anchored) return;
      const t = trigger.getBoundingClientRect();
      const m = tip.getBoundingClientRect();
      const bottom = tip.dataset.side === 'bottom' ? t.bottom + 10 + m.height <= innerHeight : t.top - 10 - m.height < 0;
      tip.style.position = 'fixed';
      tip.style.top = `${bottom ? t.bottom + 10 : t.top - 10 - m.height}px`;
      tip.style.left = `${Math.max(8, Math.min(t.left + t.width / 2 - m.width / 2, innerWidth - m.width - 8))}px`;
    }
    
    function show(root: HTMLElement, delay: number) {
      const { tip, trigger } = partsOf(root);
      if (!tip || !trigger) return;
      clearTimeout(timers.get(root));
      // Already open (the pointer came back, or crossed the gap onto the tooltip): keep it, no new delay.
      if (tip.matches(':popover-open')) return;
      timers.set(
        root,
        window.setTimeout(() => {
          if (!tip.matches(':popover-open')) tip.showPopover();
          place(tip, trigger);
        }, delay),
      );
    }
    
    function hide(root: HTMLElement, delay: number) {
      const { tip } = partsOf(root);
      clearTimeout(timers.get(root));
      timers.set(
        root,
        window.setTimeout(() => tip?.matches(':popover-open') && tip.hidePopover(), delay),
      );
    }
    
    if (typeof window !== 'undefined' && !window.__caseroomTooltip) {
      window.__caseroomTooltip = true;
      const wireAll = () => document.querySelectorAll<HTMLElement>('[data-tooltip]').forEach(wireTooltip);
      if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', wireAll);
      else wireAll();
      const rootOf = (e: Event) => (e.target as Element).closest?.<HTMLElement>('[data-tooltip]');
      document.addEventListener('pointerover', (e) => {
        const root = rootOf(e);
        if (root && !root.contains(e.relatedTarget as Node)) {
          wireTooltip(root);
          show(root, 300);
        }
      });
      document.addEventListener('pointerout', (e) => {
        const root = rootOf(e);
        // A grace period, so the pointer can cross the gap between trigger and tooltip (1.4.13: hoverable).
        if (root && !root.contains(e.relatedTarget as Node)) hide(root, 300);
      });
      document.addEventListener('focusin', (e) => {
        const root = rootOf(e);
        if (!root) return;
        wireTooltip(root);
        // Keyboard focus only: a click also focuses the trigger, and the tooltip would cover what it opened.
        if ((e.target as Element).matches(':focus-visible')) show(root, 0);
      });
      document.addEventListener('focusout', (e) => {
        const root = rootOf(e);
        if (root && !root.contains(e.relatedTarget as Node)) hide(root, 0);
      });
      document.addEventListener('pointerdown', (e) => {
        const root = rootOf(e);
        if (root) hide(root, 0);
      });
      document.addEventListener('keydown', (e) => {
        if (e.key !== 'Escape') return;
        for (const tip of document.querySelectorAll<HTMLElement>('[data-tooltip] > [role=tooltip]:popover-open')) tip.hidePopover();
      });
    }
    
    export {};
    tooltip.tsx
    import { useEffect, useRef, type ReactNode } from 'react';
    import { cn } from '@/lib/utils';
    import { wireTooltip } from './tooltip.client';
    import { tooltip } from './tooltip.variants';
    
    export interface TooltipProps {
      /** Unique on the page: the tooltip's id (the trigger's aria-describedby). */
      id: string;
      /** The text. Keep it short; it describes the trigger, it is not a place for links or buttons. */
      content: string;
      side?: 'top' | 'bottom';
      className?: string;
      /** One focusable trigger, such as an icon button. */
      children: ReactNode;
    }
    
    /** A short label shown on hover (after 300ms) and on keyboard focus; Escape hides it. */
    export function Tooltip({ id, content, side = 'top', className, children }: TooltipProps) {
      const ref = useRef<HTMLSpanElement>(null);
      useEffect(() => {
        if (ref.current) wireTooltip(ref.current);
      }, []);
      return (
        <span ref={ref} data-tooltip="" className={cn(tooltip.root, className)} style={{ anchorName: `--${id}` } as React.CSSProperties}>
          {children}
          <span id={id} role="tooltip" popover="manual" data-side={side} className={tooltip.content} style={{ positionAnchor: `--${id}` } as React.CSSProperties}>
            {content}
          </span>
        </span>
      );
    }
    tooltip.variants.ts
    /** A short label for a control, on a manual popover in the top layer. Above the trigger by default, flipped when there
     *  is no room (CSS anchor positioning; the script places it where that is missing). It fades in after a short delay
     *  on hover and at once on keyboard focus; with reduced motion it only appears. */
    export const tooltip = {
      root: 'inline-flex',
      content:
        'pointer-events-auto m-0 max-w-64 rounded-md bg-foreground px-2.5 py-1.5 text-xs leading-snug font-medium text-background shadow-md [inset:auto] opacity-0 transition-[opacity,display,overlay] transition-discrete duration-100 open:opacity-100 starting:open:opacity-0 supports-[anchor-name:--a]:[position-area:top] supports-[anchor-name:--a]:mb-2.5 supports-[anchor-name:--a]:[position-try-fallbacks:flip-block] data-[side=bottom]:supports-[anchor-name:--a]:[position-area:bottom] data-[side=bottom]:supports-[anchor-name:--a]:mt-2.5 data-[side=bottom]:supports-[anchor-name:--a]:mb-0',
    };