lmlfc-bttv/src/main.ts

const emote_regex = /bttv:([^\s]+)/g;

type Emote = {
  code: string;
  url: string;
};

async function bttv_get_url(code: string): Promise<Emote> {
  return {
    code: code,
    url: `result_${code}`,
  };
}

type EmoteMap = { [code: string]: string };

async function get_emotes(codes: Iterable<string>): Promise<EmoteMap> {
  const codes_set = new Set(codes);

  // queue emote jobs
  const queue = [...codes_set].map((code) => bttv_get_url(code));

  // run
  const result: EmoteMap = {};
  for (const job of await Promise.all(queue)) {
    result[job.code] = job.url;
  }

  return result;
}

async function process_text(text: string): Promise<string> {
  const matches = [...text.matchAll(emote_regex)];
  const emotes = await get_emotes(matches.map((elem) => elem[1]));

  for (const emote of matches.reverse()) {
    const [match, code] = emote;
    const index = emote.index ?? 0;

    text =
      text.substring(0, index) +
      emotes[code] +
      text.substring(index + match.length);
  }

  console.log(text);
  return text;
}

(() => {
  const cb_form = document.querySelector("#mgc_cb_evo_form");
  if (!(cb_form instanceof HTMLFormElement)) return;

  const bttv_btn = (() => {
    const btn = document.createElement("a");
    btn.style.setProperty("cursor", "pointer");
    btn.style.setProperty("margin-right", "4px");

    const img = document.createElement("img");
    img.setAttribute("src", chrome.runtime.getURL("bttv.png"));
    img.style.setProperty("vertical-align", "middle");

    btn.addEventListener("click", async (event) => {
      const cb_input = document.querySelector("#mgc_cb_evo_input");
      if (!(cb_input instanceof HTMLInputElement)) return;

      await process_text("bttv:foo bttv:bar bttv:foo");

      // await process_text(cb_input.value);
      // cb_input.focus();
    });

    btn.appendChild(img);
    return btn;
  })();

  cb_form.insertBefore(
    bttv_btn,
    document.querySelector("#mgc_cb_evo_form > input[type=image]:nth-child(2)"),
  );

  console.log("done.");
})();