Building a robust dialog (modal) component for my AgnosticUI library recently led me down a fascinating path. My initial plan was to create a completely independent component, leveraging the new <dialog></dialog> element for accessibility benefits. However, after thorough research, I opted for Kitty Giraudel's a11y-dialog library, creating adapters for Vue 3, Svelte, and Angular (a React adapter already exists). This decision stemmed from a careful consideration of the native <dialog></dialog> element's limitations.

The Native <dialog></dialog> Element: A Critical Evaluation

While the native <dialog></dialog> element shows promise and is actively being improved, several current shortcomings influenced my decision:

1. Backdrop Click Handling: The default behavior doesn't close the dialog when clicking outside.
2. alertdialog Role Incompatibility: The crucial alertdialog ARIA role, essential for alerts requiring user interaction and preventing backdrop/ESC closure, doesn't function correctly.
3. ::backdrop Pseudo-element Limitations: This styling element is only available when dialog.showModal() is used programmatically.
4. Styling Inconsistencies: Default styles are browser-dependent, requiring JavaScript intervention, undermining the "pure HTML" advantage.

Adam Argyle's excellent post on building with native <dialog></dialog> provides valuable workarounds, but for my needs, the complexities outweighed the benefits.

Defining Accessibility Requirements for a Dialog Component

My AgnosticUI dialog component needed to meet these crucial accessibility criteria:

1. Backdrop/ESC Closure: Closing via backdrop clicks or ESC key presses.
2. Focus Trapping: Preventing tabbing outside the component.
3. Bidirectional Tabbing: Supporting forward (TAB) and backward (SHIFT TAB) tabbing.
4. Focus Restoration: Returning focus to the previously active element upon closure.
5. Correct ARIA Attributes: Proper application of ARIA attributes and toggles.
6. Portals (Framework-Specific): Support for portals in JavaScript frameworks.
7. alertdialog Role Support: Handling alert scenarios correctly.
8. Body Scroll Prevention: Optionally preventing underlying body scrolling.
9. Avoiding Native <dialog></dialog> Pitfalls: Addressing the limitations of the native element.
10. Custom Styling and prefers-reduced-motion: Allowing custom styling and respecting user preferences.

Scott O'Hara's and Kitty's articles provide deeper dives into accessible dialog creation. These requirements clearly highlighted the limitations of relying solely on the native <dialog></dialog> element.

Auditing a11y-dialog for Accessibility

Before integrating a11y-dialog, I performed a thorough accessibility audit:

• Manual Verification: Testing functionality across browsers.
• Automated Tooling: Utilizing Lighthouse, IBM Equal Access Accessibility Checker, Deque's AXE, and WAVE.
• Screen Reader Testing: Using JAWS, NVDA, and VoiceOver.
• User Testing: (Ideally, testing with real users).

Deque Systems' research indicates automated tools only catch about 57% of accessibility issues, emphasizing the importance of manual testing and user feedback. I tested using a simple local HTML page to isolate the component from testing framework complexities.

The audit confirmed a11y-dialog's robustness and adherence to my accessibility requirements.

Framework-Specific Dialog Component Considerations

Many frameworks offer their own dialog components. While I haven't personally audited all of them, here are some resources and observations:

• Angular: Deque's 2020 audit highlighted Material and ngx-bootstrap as strong contenders.
• React: Reakit, chakra-ui, Material, reach/dialog, and @react-aria/dialog are worth exploring.
• Vue: Vuetensils, Vuetify, and PrimeVue (with a noted focus restoration issue) are options.
• Svelte: svelte-headlessui, svelterial's Material port, and svelte-a11y-dialog (especially useful for custom component creation).
• Bootstrap: Requires manual steps for accessibility compliance.

My AgnosticUI library uses a11y-dialog adapters for cross-framework compatibility.

Building Custom Design Systems: Weighing the Effort

Creating a custom dialog component for a design system requires significant effort and careful consideration of accessibility nuances. While feasible, the risk of errors is high, and leveraging existing, well-tested solutions like a11y-dialog often proves more efficient and reliable. Scott O'Hara's advice to use robust plugins like a11y-dialog to ensure consistent cross-browser experiences is compelling.

Conclusion

My choice to utilize a11y-dialog, coupled with the creation of Vue 3, Svelte, and Angular adapters, prioritized accessibility and efficiency. While building a custom component was an option, the potential for errors and the existing quality of a11y-dialog made it the superior choice. This journey highlighted the importance of thorough accessibility audits and the value of leveraging well-maintained libraries. The adaptability of a11y-dialog, extending its functionality to create drawer components, further solidified its value within my library.

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