Have you ever installed a dependency, imported it just like the README instructs, and immediately been met with strange TypeScript errors about default imports, the output module format, or ESM/CommonJS interoperability? When everything works at runtime but TypeScript complains, you might wonder, is this a TypeScript bug? Or… are the types wrong?
The JavaScript module and package publishing landscape is complicated. Nearly one third of the most popular types-included npm packages have some sort of module-related typings issue that can cause confusion for users. But things are starting to improve. In this talk, we’ll:
- explore how we got here—why are things complicated?
- develop a simple and accurate mental model for how TypeScript sees packages
- see how the `arethetypeswrong` tool can help catch issues before publishing
- look at trends in the `arethetypeswrong` data for popular packages over time
- discuss next steps for making the typed package ecosystem better