| Enums aren’t interchangeable, which is either a good thing or a bad thing, depending. Let’s say I have an Icon component with props like: type IconProps = { size: “s” | “m” | “l” }
And then let’s say I have a Button component but there’s no small size: type ButtonProps = { size: “m” | “l” }
If I use string unions I can happy assign one size to another: const Button = ({ size }: ButtonProps) => (
<button><Icon size={size} />
)
If I used enums (ButtonSize and IconSize) then that would not be possible and TypeScript would complain.So the question is: Is that a bad thing? And the answer depends on your domain. If you have reason to believe that in your domain people are likely to map between two incompatible namespaces, then enums could help. And string unions could let through some bugs. In my experience that’s never been a real risk so I prefer string unions. The other thing enums can get you is you can rename the variable without changing the values. So if your strings are persisted to the database and you don’t want to change them, but you do want them to have a slightly new meaning, you could rename the enum key, and get the new name in code, while keeping the old string value. |