The Japan difference for life expectancy could just be because Japanese men work themselves to death more often than not. Women do as well, but there's also lots of pressure to get them out of the workforce.
Using `as const` will report both the 2nd and 3rd lines as type errors. You've been able to do this in TypeScript for a while even before they introduced the `as const` syntax.
React can be used from a CDN as well, including using it with JSX. Although using JSX from CDN scripts is a bad idea in production because it's slower.
It's a dev dependency because they use it in unit tests but it's also a peer dependency, meaning that if you want to use the library you need to include moment.