pages/js/main.js

const $ = _ => document.querySelector(_);

const DiscordApi = {
  getUser: async () => {
    if (typeof localStorage.getItem('token') !== "string")
      return null;

    const req = await fetch('https://discord.com/api/v10/users/@me', {
      headers: {
        'Authorization': `Bearer ${localStorage.getItem('token')}`
      }
    });

    const res = await req.json();

    DiscordApi.refreshToken();

    return res;
  },
  refreshToken: () => {
    if (typeof localStorage.getItem('refresh') !== "string")
      return null;

    fetch('https://crss-api.theclashfruit.workers.dev/refresh', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({ authCode: localStorage.getItem('refresh') })
    })
      .then(res => res.json())
      .then(res => {
        localStorage.setItem('token', res.access_token)
        localStorage.setItem('refresh', res.refresh_token)
      })
  }
}

const displayUser = async () => {
  const user = await DiscordApi.getUser()

  $('.userButton').innerText = user.global_name
}

displayUser();