Deno script for finding Mastodon accounts from an account's followers list.

main.ts

import { Rettiwt } from "npm:rettiwt-api";

const fediHandle = /@[\w.-]+@[\w.-]+/;

const apiKey = Deno.env.get("TWITTER_API_KEY");
const username = Deno.args.at(-1);

if (username === undefined)
  throw new Error("You must pass your Twitter username as an argument.");

if (apiKey === undefined)
  throw new Error(
    "You must pass your Twitter API key, with the environment variable TWITTER_API_KEY. Use https://chromewebstore.google.com/detail/x-auth-helper/igpkhkjmpdecacocghpgkghdcmcmpfhp."
  );

const rettiwt = new Rettiwt({
  apiKey: apiKey,
});

const user = await rettiwt.user.details(username);
if (!user) {
  throw new Error("User with that username not found.");
}

const following = [];
let cursor = undefined;

while (true) {
  const chunk = await rettiwt.user.following(user.id, 100, cursor?.value);
  if (chunk.list.length === 0) break;

  following.push(...chunk.list);
  cursor = chunk.next;
  // wait a second before getting the next chunk, I don't want to risk getting banned
  await new Promise((r) => setTimeout(r, 1000));
}

const handles = following
  .map((u) => u.fullName.match(fediHandle) ?? u.description?.match(fediHandle))
  .filter((h) => h);
const entries = handles.map((h) => `${h},true,false,`);

await Deno.writeTextFile("following.csv", entries.join("\n"));