saveAllFocusableElements = (modal, array) => {
        const focusableElements = getFocusableElements(modal);

        /**
         * Save first and last elements (trap focus inside modal)
         */
        array[0] = focusableElements[0];
        array[1] = focusableElements[focusableElements.length - 1];
    }
Saves all focusable elements inside modal, into the array
@param {HTMLElement} modal
@param {Element[]} array