export function jsonResponse(body, init = {}) {

const headers = new Headers(init.headers);

headers.set("content-type", "application/json; charset=utf-8");

headers.set("x-content-type-options", "nosniff");

return new Response(JSON.stringify(body), { ...init, headers });

}

export async function readLimitedBytes(response, maxBytes) {

const reader = response.body?.getReader();

if (!reader) return new Uint8Array();

const chunks = [];

let size = 0;

while (true) {

const { done, value } = await reader.read();

if (done) break;

size += value.byteLength;

if (size > maxBytes) {

await reader.cancel();

throw new Error("RESPONSE_TOO_LARGE");

}

chunks.push(value);

}

const output = new Uint8Array(size);

let offset = 0;

for (const chunk of chunks) {

output.set(chunk, offset);

offset += chunk.byteLength;

}

return output;

}

export async function readLimitedRequestJson(request, maxBytes) {

const declared = Number(request.headers.get("content-length") ?? 0);

if (Number.isFinite(declared) && declared > maxBytes) {

throw new Error("REQUEST_TOO_LARGE");

}

const bytes = new Uint8Array(await request.arrayBuffer());

if (bytes.byteLength > maxBytes) throw new Error("REQUEST_TOO_LARGE");

return JSON.parse(new TextDecoder().decode(bytes));

}

export function createTimeout(

milliseconds,

setTimeoutImpl = setTimeout,

clearTimeoutImpl = clearTimeout,

) {

const controller = new AbortController();

const timer = setTimeoutImpl(() => controller.abort(), milliseconds);

return {

signal: controller.signal,

dispose: () => clearTimeoutImpl(timer),

};

}