IE11 add/remove/contains class for SVG

ie11svg.js

if (!("classList" in SVGElement.prototype)) {
  Object.defineProperty(SVGElement.prototype, "classList", {
    get() {
      return {
        contains: className => {
          return this.className.baseVal.split(" ").indexOf(className) !== -1;
        },
        add: className => {
          return this.setAttribute('class', this.getAttribute('class') + ' ' + className);
        },
        remove: className => {
          var removedClass = this.getAttribute('class').replace(new RegExp('(\\s|^)' + className + '(\\s|$)', 'g'), '$2');
          if (this.classList.contains(className)) {
            this.setAttribute('class', removedClass);
          }
        }
      };
    }
  });
}

Toggle, if needed.

toggle: (name, flag = !this.contains(name)) {
    return flag ? (this.add(name), true) : (this.remove(name), false);
}

toggle: toggle.bind(returnedObject)

Does not work for me.

Has anyone thought about how to incorporate Replace? Looking to avoid refactoring but potentially could make existing codebase work with Add or Remove so this is very much appreciated.

How to add toggle method too?

How to add toggle method too?

https://gist.github.com/EvanAgee/350b5072e1ec3d82d34cc6a735914eff#gistcomment-2992240

I saw that but don't get how to implement in the original gist