Typescript-eslint - unsafe assignment of an 'any' value

const [currentIndex, setCurrentIndex] = useState(Math.floor((slidesLength / 2)))
  const percent = (100 * (currentIndex + 1)) / slidesLength;

  if (typeof window !== "undefined") {
    window.addEventListener('storage', () => {
      const index: number =         JSON.parse(localStorage.getItem('currentIndex')!) ?? Math.floor((slidesLength / 2));
      setCurrentIndex(index)
    })
  }

const [currentIndex, setCurrentIndex] = useState(Math.floor((slidesLength / 2)))
  const percent = (100 * (currentIndex + 1)) / slidesLength;

  if (typeof window !== "undefined") {
    window.addEventListener('storage', () => {
      const index: number =         JSON.parse(localStorage.getItem('currentIndex')!) ?? Math.floor((slidesLength / 2));
      setCurrentIndex(index)
    })
  }

--23:13  Error: Unsafe assignment of an `any` value.  @typescript-eslint/no-unsafe-assignment
23:32  Warning: Forbidden non-null assertion.  @typescript-eslint/no-non-null-assertion
--24:23  Error: Unsafe argument of type `any` assigned to a parameter of type `SetStateAction<number>`.  @typescript-eslint/no-unsafe-argument
--33:28  Error: Invalid type "string | undefined" of template literal expression.  @typescript-eslint/restrict-template-expressions

--23:13  Error: Unsafe assignment of an `any` value.  @typescript-eslint/no-unsafe-assignment
23:32  Warning: Forbidden non-null assertion.  @typescript-eslint/no-non-null-assertion
--24:23  Error: Unsafe argument of type `any` assigned to a parameter of type `SetStateAction<number>`.  @typescript-eslint/no-unsafe-argument
--33:28  Error: Invalid type "string | undefined" of template literal expression.  @typescript-eslint/restrict-template-expressions