WordPress - JS for uploading images to widget

wpAdminWidgetImageUploader.js

/** 
*  Steps:
*  1. Pop this into your theme's assets/js directory, set the filename as widgets.js (or add JS to existing widgets.js)
*  2. See the other gist for widget PHP instructions if you haven't already
*  3. Profit++
*/
// ============================================
// Custom JavaScript used in Widgets (WP Admin)
// ============================================
// Image uploader
// https://vedmant.com/using-wordpress-media-library-in-widgets-options/
jQuery(document).ready(function ($) {
    console.log('started');
    $(document).on("click", ".upload_image_button", function (e) {
       e.preventDefault();
       var $button = $(this);
       console.log('clicked');
       // Create the media frame.
       var file_frame = wp.media.frames.file_frame = wp.media({
          title: 'Select or upload image',
          library: { // remove these to show all
             type: 'image' // specific mime
          },
          button: {
             text: 'Select'
          },
          multiple: false  // Set to true to allow multiple files to be selected
       });
  
       // When an image is selected, run a callback.
       file_frame.on('select', function () {
          // We set multiple to false so only get one image from the uploader
          var attachment = file_frame.state().get('selection').first().toJSON();

          $button.siblings('input').val(attachment.url);
       });
  
       // Finally, open the modal
       file_frame.open();
    });
 });