Chrome APIs

type SharedStorage = {
  worklet: { addModule: (url: string) => Promise<void> };
  set: (key: string, value: string, options?: { ignoreIfPresent?: boolean }) => Promise<void>;
  run: (operation: string, options?: { data?: Record<string, unknown> }) => Promise<void>;
};

type PeriodicSyncRegistration = ServiceWorkerRegistration & {
  periodicSync: { register: (tag: string, options: { minInterval: number }) => Promise<void> };
};

export const schedulePeriodicRefresh = async (tag: string, minIntervalMs: number): Promise<boolean> => {

type LaunchParams = { files: FileSystemFileHandle[] };
type LaunchQueue = { setConsumer: (consumer: (params: LaunchParams) => void) => void };

export const handleLaunchedFiles = (onFiles: (files: File[]) => void): void => {
  const launchQueue = (window as { launchQueue?: LaunchQueue }).launchQueue;

type SyncRegistration = ServiceWorkerRegistration & { sync: { register: (tag: string) => Promise<void> } };

export const scheduleOfflineAction = async (tag: string, replayNow: () => Promise<void>): Promise<void> => {
  const registration = await navigator.serviceWorker.ready;
  const canBackgroundSync = "sync" in registration;

const injectedUrls = new Set<string>();

export const prerenderOnHoverIntent = (link: HTMLAnchorElement, dwellMs = 200) => {
  if (!(globalThis as any).HTMLScriptElement?.supports?.("speculationrules")) return;
  let timer = 0;

type Row = { id: number; status: string; durationMs: number };

export const logBatchResult = async (rows: Row[], errors: { field: string; message: string }[]) => {
  console.table(rows, ["id", "status", "durationMs"]);

.long-page section {
  content-visibility: auto;
  contain-intrinsic-size: auto 480px;
}

// @types/dom-webcodecs isn't installed in this repo, so VideoDecoder/VideoFrame/
// EncodedVideoChunk aren't typed here — cast to `any` rather than pretend otherwise.
export const decodeFrames = (chunks: any[], onFrame: (frame: any) => void): Promise<void> => {
  const Decoder = (globalThis as any).VideoDecoder;
  const decoder = new Decoder({

// TypeScript hasn't bundled URLPattern into its DOM types yet, so this repo's tsconfig
// doesn't know about it either. One cast at the constructor keeps everything below fully
// typed instead of leaking `any` through the rest of the file.
type UrlMatch = { pathname: { groups: Record<string, string | undefined> } };
type UrlPatternLike = { exec: (input: { pathname: string }) => UrlMatch | null };

h1, h2, .card-title {
  text-wrap: balance;
  max-width: 40ch;
}

<user-card>
  <template shadowrootmode="open">
    <style>
      :host { display: block; border: 1px solid #ddd; border-radius: 8px; padding: 1rem; }
      .name { font-weight: 600; margin: 0; }

export const openModal = (modalRoot: HTMLElement) => {
  const siblings = Array.from(document.body.children).filter(
    (el): el is HTMLElement => el !== modalRoot && el instanceof HTMLElement,
  );
  siblings.forEach((el) => {

.toast {
  display: none;
  opacity: 0;
  translate: 0 12px;
  transition: opacity 0.2s ease, translate 0.2s ease, display 0.2s allow-discrete;

// No @webgpu/types in this repo's tsconfig, so these casts stand in for the
// missing ambient types. Swap them for the real types in a project that has
// @webgpu/types installed.
export const doubleOnGpu = async (input: Float32Array): Promise<Float32Array> => {
  const gpu = (navigator as any).gpu;

// TypeScript's DOM lib has FileSystemFileHandle but not window.showOpenFilePicker
// itself yet -- narrow cast for just the missing entry point.
type ShowOpenFilePicker = (opts: {
  types: { description: string; accept: Record<string, string[]> }[];
}) => Promise<FileSystemFileHandle[]>;

// TypeScript's DOM lib has neither URLPattern nor the Navigation API yet --
// narrow casts for just the shapes this snippet actually uses.
type UrlMatch = { pathname: { groups: Record<string, string | undefined> } };
type UrlPatternLike = { test: (i: { pathname: string }) => boolean; exec: (i: { pathname: string }) => UrlMatch | null };
const URLPattern = (globalThis as any).URLPattern as new (init: { pathname: string }) => UrlPatternLike;

type TaskPriority = "user-blocking" | "user-visible" | "background";
type PostTask = (cb: () => void, opts?: { priority?: TaskPriority }) => Promise<void>;

const postTask = (globalThis as { scheduler?: { postTask: PostTask } }).scheduler?.postTask;

<button id="delete-trigger">Delete project</button>

<dialog id="confirm-dialog" closedby="any" aria-labelledby="confirm-title">
  <form method="dialog">
    <h2 id="confirm-title">Delete this project?</h2>

.trigger {
  anchor-name: --tooltip-trigger;
}

.tooltip {

// togglePopover's { source } option is current spec but not yet in TypeScript's DOM lib.
type TogglePopover = (options?: { source?: HTMLElement; force?: boolean }) => void;
const menu = document.querySelector<HTMLElement>("#user-menu")!;
const trigger = document.querySelector<HTMLButtonElement>("#user-menu-trigger")!;

export const swapView = (activeEl: HTMLElement, render: () => void) => {
  if (!document.startViewTransition) {
    render();
    return;
  }