Adds an button to the post creation form that uploads an image and inserts it in the post

BitcoinTalkImageUploadButton.js

// ==UserScript==
// @name         Bitcointalk Image Upload Button
// @version      0.1
// @description  Adds an button to the post creation form that uploads an image and inserts it in the post
// @author       TryNinja
// @match        https://bitcointalk.org/index.php?action=post*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=bitcointalk.org
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

const imgButton = document.querySelector('a:nth-child(24)');

const imgUploadButton = document.createElement('a');
imgUploadButton.innerHTML = `<a href="javascript:void(0);" onclick="document.getElementById('uploadImage').click()"><img src="https://i.imgur.com/ukC9kf1.png" align="bottom" width="23" height="22" alt="Upload and Insert Image" title="Upload and Insert Image"></a>`;
imgButton.after(imgUploadButton);

const uploadInput = document.createElement('input');
uploadInput.id = 'uploadImage';
uploadInput.type = 'file';
uploadInput.accept = 'image/*';
uploadInput.style.display = 'none';
imgButton.after(uploadInput);

const insertImageUrl = imgUrl => {
  const postTextArea = document.querySelector('textarea');
  postTextArea.value += `\n[img]${imgUrl}[/img]`;
};

uploadInput.onchange = async () => {
  const { files } = uploadInput;
  if (files[0].size) {
    const formData = new FormData();
    formData.append('type', 'file');
    formData.append('image', files[0]);

    console.log('uploading image');

    const upload = await fetch('https://api.imgur.com/3/image', {
      method: 'POST',
      headers: { authorization: 'Client-ID 09727b421c2303e' },
      body: formData,
    });

    const result = await upload.json();

    if (result.success) {
      insertImageUrl(result.data.link);
    }
  }
};

})();