I already installed the ide-typescript and ide-ui package, but I see no difference, no tslint, no autocomplete. Am I missing something?
No, this is reoccurring theme with the IDE support in general. A bunch of us are experiencing this. I’m trying to use the C# packages (with the required UI package) and I have absolutely no difference on my end. Multiple reports of this issue on their repo, but no fixes and no changes have been synced yet. You’re not alone. A bummer for those of us who have been wanting to use Atom as an IDE for some time. Hoping this is fixed soon or at least someone from the team hops on and updates us on the progress.
There is not much to go on with your description. A whole screen picture might give some clues.
Do note that the functionality will only be active when the text is identified as
Typescript. You should see this in the bottom right corner. Clicking on this also makes it possible to change it.