Gentu Paster.js

// ==UserScript==
// @name        Gentu Paster
// @namespace   Violentmonkey Scripts
// @match       https://gentu.io/patients/*/clinical_history/letters/*
// @grant       none
// @version     1.0
// @author      -
// @require     https://cdn.jsdelivr.net/gh/CoeJoder/waitForKeyElements.js@v1.2/waitForKeyElements.js
// @description 26/05/2020, 20:58:38
// ==/UserScript==

window.addEventListener('load', function() {
  waitForKeyElements("[contenteditable]", (element) => {
    element.addEventListener('paste', (e) => {
      setTimeout(() => {
        for(table of element.querySelectorAll('table:not(.layout-table)')) {
          table.classList.add('layout-table')
        } 
      }, 100)
      console.log('pasted into contenteditable')
    })
  });

  document.addEventListener('keyup', (e) => {
    if(e.key.toLowerCase() == 'v' && e.altKey == true && e.ctrlKey == true) {
      var div = document.createElement('div')
      div.style.cssText = 'position: fixed; top: 10pt; bottom: 10pt; left: 10pt; right: 10pt; box-shadow: 3px 3px 10px rgba(0,0,0,0.25); border: 1px solid grey; padding: 8pt; z-index: 2000; background: white; border-radius: 4pt;'
      div.setAttribute('contenteditable', true)
      document.body.appendChild(div)

      div.addEventListener('paste', (e) => {
        var pastedHtml = e.clipboardData.getData('text/html')
        if(pastedHtml.length > 0) {
          setTimeout(() => {
            clean(div)
          }, 100)
        }
      })

      div.addEventListener('copy', (e) => {
        setTimeout(() => { div.remove() }, 100)
      })
    }
  })
}, false);



function clean(parent) {
  function unwrap(wrapper) {
    // place childNodes in document fragment
    var docFrag = document.createDocumentFragment();
    while (wrapper.firstChild) {
        var child = wrapper.removeChild(wrapper.firstChild);
        docFrag.appendChild(child);
    }

    // replace wrapper with document fragment
    wrapper.parentNode.replaceChild(docFrag, wrapper);
  }

  for (node of parent.querySelectorAll('*')) {
      node.removeAttribute('colspan')
  }
  for (node of parent.querySelectorAll('*')) {
      if (node.style.getPropertyValue('text-decoration-line')) {
          node.style.removeProperty('text-decoration-line')
          wrapped = "<u>" + node.innerHTML + "</u>";
          node.innerHTML = wrapped;
      }
  }
  for (node of parent.querySelectorAll('*')) {
      if (node.style.getPropertyValue('font-weight') == 'bold') {
          node.style.removeProperty('font-weight')
          wrapped = "<strong>" + node.innerHTML + "</strong>";
          node.innerHTML = wrapped;
      }
  }
  for (node of parent.querySelectorAll('a')) {
      unwrap(node)
  }


  // For tables consisting of a single row, which are themselves direct deescendants of another table, append row to parent table.
  for (table of parent.querySelectorAll('td > table')) {
      if (table.rows.length == 1) {
          table.closest('tr').insertAdjacentElement('afterend', table.rows[0])

      }
  }

  for (n of parent.querySelectorAll('[style]')) {
      n.removeAttribute('style')
  }

  // Remove wrapping table if all child rows only have a single cell
  for (table of parent.querySelectorAll('table')) {
      var singleCelled = [...table.rows].every( (x) => { return x.cells.length <= 1 })
      if (singleCelled) {
          for(var row of table.rows) {
              var cell = row.cells[0]
              if (cell) {
                  var div = document.createElement('div')
                  while (cell.firstChild) {
                      div.appendChild(cell.firstChild)
                  }
                  table.insertAdjacentElement('beforebegin', div);
              }
          }   
          table.remove()
      }
  }

  var walk = document.createTreeWalker(parent,NodeFilter.SHOW_TEXT,null,false);
  while(node = walk.nextNode()) {
      node.nodeValue = node.nodeValue.replace(/( {2,})/gi,'').trim()
  }

  for (n of parent.querySelectorAll('*')) {
      if (n.innerText == '') {
          n.remove()
      } else {
          if (n.tagName == 'STRONG') {
              n.prepend(document.createElement('br'));
          }
      }
  }
}