REST Countries API with color theme switcher solution

Im not familiar with fetching data so i wanna work on that more often. so i picked this challenge. im not quit sure if this is how it should be because i used react-router. I found some difficulty of loading pages. so if i select a region and want to get back to home page i have to wait for the data to be fetched again and make some delay. i know its normal but the thing is i have to wait until its fetched then it take me to the page, so it loads to a bad experience because the user doesnt know if its loading or not. i want to make the user switch to the home page then load it with an animation