youtube-enhancer-script-select-japanese-machineTranslation.js

(async () => {
  const wait = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

  const strings = {
    subtitle: "字幕",
    english: "英語",
    targetLanguage: "日本語",
    machineTranslation: "自動翻訳",
  };

  const settingsButton = document.querySelector(".ytp-settings-button");

  const findMenuItem = (text) => {
    const menuItems = [...document.querySelectorAll(".ytp-menuitem")];
    return menuItems.find((item) => item.innerText.includes(text));
  };

  try {
    // open
    settingsButton.click();
    await wait(100);
    // close
    settingsButton.click();
    await wait(100);

    findMenuItem(strings.subtitle).click();
    await wait(500);

    // if target language is provided? choose it
    if (findMenuItem(strings.targetLanguage)) {
      findMenuItem(strings.targetLanguage).click();
      return;
    }

    // choose english and machine translation
    findMenuItem(strings.english).click();
    await wait(2000);

    findMenuItem(strings.subtitle).click();
    await wait(100);

    findMenuItem(strings.machineTranslation).click();
    await wait(500);

    findMenuItem(strings.targetLanguage).click();
  } catch (error) {
    console.error(error);
  }
})();