code: function closest (el, selector, scope) {
    scope = scope || document.documentElement
  
    // walk up the dom
    while (el && el !== scope) {
      if (matches(el, selector)) return el
      el = el.parentNode
    }
  
    // check scope for match
    return matches(el, selector) ? el : null
  }
docs: Closest
  
  @param {Element} el
  @param {String} selector
  @param {Element} scope (optional)