Use if else to declar a `let` or `const` to use after the if/else?

I'm not sure why but it seems that I can't call the let or const variables if I declare them in an if/else statement

if (withBorder) {
  const classes = `${styles.circularBorder} ${styles.dimensions} ${styles.circularPadding} row flex-items-xs-middle flex-items-xs-center`;
} else {
  const classes = `${styles.dimensions} ${styles.circularPadding} row flex-items-xs-middle flex-items-xs-center`;
}
return (
  <div className={classes}>
    {renderedResult}
  </div>
);

If I use this code it says that classes is not defined

But if I change the const to var classes is defined but I get a warning about classes used outside of binding contextand all var declarations must be at the top of the function scope

How could I fix this?