Method addClass

frontend/src/ts/utils/dom.ts:281–293

* Add a class to the element

(className: string | string[])

   * Add a class to the element
   */
  addClass(className: string | string[]): this {
    if (Array.isArray(className)) {
      this.native.classList.add(...className);
    } else {
      if (className.includes(" ")) {
        return this.addClass(
          className.split(" ").filter((cn) => cn.length > 0),
        );
      }
      this.native.classList.add(className);
    }
    return this;
  }

  /**
   * Remove a class from the element