get-property-transform.js

Document.prototype.transformProperty = function (selector, property, transformGetter, transformSetter) {
  Object.defineProperty(document.querySelector(selector), property, {
    get: function () {
      return transformGetter(document.querySelector(selector).cloneNode()[property]);
    },
    set: function (value) {
      let clone = document.querySelector(selector).cloneNode(true);
      clone.value = transformSetter(value);
      document.querySelector(selector).replaceWith(clone);
    }
  });
};