Accessibility

Calling something accessible is easy and usually wrong, so here is the split.

Built in

• <opengrid-table> and <opengrid-pivot> are native <table> elements. <opengrid-grid> uses role="grid", because it takes over the arrow keys — for a report table that would be the wrong promise, which is why the table exists.
• Every feature is keyboard-operable. The grid follows the WAI-ARIA grid pattern; the key matrix is in The public API.
• Every state change goes through one polite live region.
• The component’s own words are English and overridable with set_texts. A lang given with them goes onto the elements that carry those texts, never onto the data. German ships with the package as @casoon/opengrid/texts/de (Texts).
• A pivot group whose value is NULL is named (no value), one whose value is the empty string (empty): an empty header cell is silence to a screen reader.

Machine-readable by the same means

What makes the grid usable with a screen reader makes it readable for programs, so there is no second, machine-only layer to keep in step:

• The accessibility tree is the interface. Roles, names, aria-rowcount for the whole result and aria-rowindex per row tell a test, an automation tool or a browser agent what the grid holds and where it is, even though only a window of rows is in the DOM.
• The data is open at every step: the schema is a JSON document, a query is a JSON AST, the view is JSON, and an export is CSV or JSON of what the reader sees, or of every match.
• Structured data (schema.org, JSON-LD) stays the page’s: only the page knows what the data set is. The grid adds none of its own.

Without JavaScript, the rows the element draws don’t exist. So a page can write its data as a plain <table> inside the element: that’s what a reader or crawler without script reads, and what stays when the module can’t load. Once the element has rendered, it replaces that table (Data without JavaScript).

Verified by tests, on every commit

Roles, accessible names, aria-rowcount / aria-rowindex / aria-sort / aria-selected, the roving tabindex and the keyboard matrix, target sizes, and the language of the component’s words versus the page’s data. The Playwright suite in tests/e2e/ runs axe-core over the rendered elements.

tests/e2e/announcements.spec.js records the status line’s successive states, so an announcement that fires twice, never, or too early to survive the next result is a failing test. The first time it ran, it found that turning a page announced nothing: the row count is the same on every page, so the live region repeated itself while the content changed.

Not yet verified

A screen reader has not been through the finished V1. The protocol exists and is the last open item before a release. CI runs the e2e suite in Chromium; before a release, just e2e-browsers runs it in Firefox and WebKit too, at a desktop viewport.

So: the structure is tested hard, the experience is not signed off. Until it is, treat the accessibility of this library as well-built and unaudited.