[throw49sjwo1]

> And nobody uses most of it!

Everybody who does Express, React, or any other popular advanced libraries with TypeScript is using these features. Some things are simply more useful to libraries than line of business code - that's fine. The line of business code is much better thanks to it.

[leetharris]

> Everybody who does Express, React, or any other popular advanced libraries with TypeScript is using these features.

This is very true and my original post was short sighted. You could, of course, make most upstream dependencies without modern language features. However, their complex jobs get much easier with these features.

Downstream, business logic is much easier to implement without these features compared to complex, low level functionality.

[anon7000]

For sure! In a basic API endpoint, I don’t need advanced typescript features.

But if I’m writing a module that a lot of other consumers in the codebase will use, and I want to make their lives easy, I might use a lot of advanced TS features to make sure than type safety & inference works perfectly within the module. Whoever consumes it can then rely on that safety, but also the convenience. The module could have some convoluted types just to provide really clean and correct auto-complete in a certain method. But most people don’t need to worry about how that works

[nosefurhairdo]

Yeah I was confused by this point as well. Especially because many of the recent Typescript releases are just improving performance or handling more cases (without needing to learn new syntax).

[tannhaeuser]

React and Expressjs predate typescript, Expressjs considerably so.

[throw49sjwo1]

Doesn't matter, I'm talking about the type definitions - @types/react, @types/react-dom and @types/express.