/**
 * Test-environment shim that lets Stencil detect constructable stylesheet
 * support under jsdom.
 *
 * Spark shares one ~400KB global stylesheet across every shadow root through a
 * single constructable `CSSStyleSheet`. When Stencil cannot detect support for
 * that API it falls back to injecting a `<style>` element into *every* shadow
 * root, so jsdom re-parses those 400KB once per Spark element. That is enough to
 * take a moderate test suite past Node's 4GB heap limit.
 *
 * Stencil's detection needs two things: a truthy `document.adoptedStyleSheets`,
 * and a `CSSStyleSheet` that is constructable and has `replaceSync`. Once it
 * detects support it also reads and writes `adoptedStyleSheets` on each shadow
 * root, so that needs to exist too. jsdom supplies only the bare `CSSStyleSheet`
 * constructor, so Stencil takes the fallback. Supplying all three missing pieces
 * keeps Spark on the shared-stylesheet path.
 *
 * Neither upgrading Spark nor upgrading jsdom removes the need for this. jsdom
 * has never shipped `adoptedStyleSheets` (see
 * https://github.com/jsdom/jsdom/issues/3998, which recommends this same
 * approach). Each piece is filled in only when it is missing, so the shim
 * retires itself if jsdom ever implements the API.
 *
 * The stylesheet text is never applied, because jsdom does not implement the
 * shadow DOM cascade. That is equally true of the `<style>` element the fallback
 * injects, so this costs no style fidelity.
 *
 * See COMUI-5120.
 */
/**
 * Fills in the constructable stylesheet APIs that jsdom is missing.
 *
 * Importing this module applies the shim to `globalThis`, which is all a Jest
 * `setupFiles` entry needs. Call this directly only if you patch a different
 * global, for example from a custom Jest environment.
 *
 * @param globalObject the environment to patch, normally `globalThis`
 * @returns true when the environment is a DOM the shim can support
 */
declare function shimConstructableStyleSheets(globalObject: unknown): boolean;

export { shimConstructableStyleSheets };