Get list of ASNs ordered by prefix count

type Cloudflare = {

  token: string;

  email: string;

  key: string;

};

/**

 * Get list of ASNs ordered by prefix count

 * Get the full list of autonomous systems on the global routing table ordered by announced prefixes count. The data comes from public BGP MRT data archives and updates every 2 hours.

 */

export async function main(

  auth: Cloudflare,

  country: string | undefined,

  limit: string | undefined,

  format: "JSON" | "CSV" | undefined

) {

  const url = new URL(

    `https://api.cloudflare.com/client/v4/radar/bgp/top/ases/prefixes`

  );

  for (const [k, v] of [

    ["country", country],

    ["limit", limit],

    ["format", format],

  ]) {

    if (v !== undefined && v !== "") {

      url.searchParams.append(k, v);

    }

  }

  const response = await fetch(url, {

    method: "GET",

    headers: {

      "X-AUTH-EMAIL": auth.email,

      "X-AUTH-KEY": auth.key,

      Authorization: "Bearer " + auth.token,

    },

    body: undefined,

  });

  if (!response.ok) {

    const text = await response.text();

    throw new Error(`${response.status} ${text}`);

  }

  return await response.json();

}