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type ViteManifestEntry = {
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  file: string;
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  css?: string[];
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  imports?: string[];
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};
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type ViteManifest = Record<string, ViteManifestEntry>;
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let manifestPromise: Promise<ViteManifest | null> | null = null;
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async function fetchManifest(env: Env): Promise<ViteManifest | null> {
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  if (!env.ASSETS) {
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    return null;
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  }
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  const url = new URL("/manifest.json", "https://assets.local");
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  const response = await env.ASSETS.fetch(new Request(url.toString()));
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  if (!response.ok) {
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    return null;
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  }
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  return (await response.json()) as ViteManifest;
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}
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export async function getClientManifest(env: Env): Promise<ViteManifest | null> {
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  if (import.meta.env.DEV) {
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    return null;
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  }
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  if (manifestPromise) {
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    return manifestPromise;
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  }
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  const promise = fetchManifest(env);
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  manifestPromise = promise;
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  promise.catch(() => {
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    manifestPromise = null;
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  });
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  return promise.catch(() => null);
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}