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Using TypeScript with React

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Re: Using TypeScript with React

#31

Post by jinushaun »

Disappointed that the article alluded to but never explains why classes should be avoided in Typescript. (Which I agree, btw)

If you’re used to classes, it’s really tempting to create classes for your models. But in Typescript, which gets compiled down to plain old JavaScript, you spend a lot of your time dealing with JSON and plain old JavaScript objects (POJO). These don’t have methods. These don’t have private members. These don’t have constructors.

You actually don’t need any of that. You just want type safety around your JSON and POJO. That’s why more often than not, you’re going to be using interface.

I’m not saying never use classes. But don’t use classes to define models. Use classes for controllers.

Re: Using TypeScript with React

#32

Post by fabian2k »

h0h0h0h0111 wrote: post #22

I've been writing Typescript with React for quite a while now and these are my feelings so far: - Typescript type system is pretty awesome, and allows the expression of some things really elegantly; in particular, string literal types are quite cool for component props that feel "htmly", union and intersection types are great for making reusable/generic components and Partial is cool for making typesafe component sta…

> ... but docs for anything React related to Typescript (types of components, etc) are harder to come by

I just saw this linked today and didn't look it through entirely, but this React+Typescript cheat sheet looks very interesting for React-specific issues you might encounter with Typescript:

https://github.com/typescript-cheatsheets/react-typescript-c...

For example it explained an issue with the type inference for custom hooks that confused me somewhat earlier.

I really like Typescript so far, but you can easily encounter situations that are hard to figure out with only basic Typescript knowledge, especially when interacting with more complex libraries. This probably gets better with more Typescript experience, but it can be a serious speed bump as a Typescript beginner.

Re: Using TypeScript with React

#33

Post by aczerepinski »

manishsharan wrote: post #5

If you are going to learn a new programming language for web UI, why not go for Elm ? You get so much more than just static types with Elm.

I've tried Elm and I think it's really great. I've watched a handful of Evan's conference talks and I respect him a lot.

However, when I choose what tech to go deep in with my limited free time, I want to see more than zero mentions of it in the "who is hiring" threads. I don't feel like Elm's traction has gained any in the two years since I first dabbled in it. If I was in a position to pick the tech stack for my work, I'd give Elm serious consideration though.

Re: Using TypeScript with React

#35

Post by jillesvangurp »

Typescript is a lot easier to deal with if you stop treating it as optional and do it from day 1. Avoid using the any type and things fall in to place. If it's tedious, you're probably doing something wrong or sub-optimal. Or you're just dealing with a bit of hairy old javascript that probably needs a bit of refactoring in any case.

IMHO we're reaching the point where typescript (or similar languages) should be used by default over untyped javascript in professional environments. It's like having tests, which are also not generally considered optional. I've been in CTO type roles and already insist on it when I can. I don't think I'm alone in this and many organizations only do typescript at this point.

Re: Using TypeScript with React

#36

Post by bauerd »

I'm currently trying to revive a 2yrs old codebase written with TypeScript/React/Redux. I made the capital error of not checking in node_modules apparently or pinning versions (ie using yarn or npm shrinkwrap), as I now get tons and tons of type errors from dependencies on build. Problem seems to be that all the @types packages are somehow out of sync/broken/hell I don't know. I also don't have access to CI logs anymore so I can't figure out which versions it used to resolve to …

The @types definition packages for react-router, redux-thunk, etc. give me "error TS2605: JSX element type X is not a constructor function for JSX element". Most popular answer on GitHub is to rm -rf node_modules and rebuild, however that does nothing for me. I tried upgrading some @types selectively and triple-double checked that the resolved versions make sense, but nothing so far.

A codebase that used to build cleanly now throws ~30 errors on build, without any changes to it. Insane. Always pin your exact versions in JS land …

Re: Using TypeScript with React

#37

Post by kyranjamie »

bauerd wrote: post #36

I'm currently trying to revive a 2yrs old codebase written with TypeScript/React/Redux. I made the capital error of not checking in node_modules apparently or pinning versions (ie using yarn or npm shrinkwrap), as I now get tons and tons of type errors from dependencies on build. Problem seems to be that all the @types packages are somehow out of sync/broken/hell I don't know. I also don't have access to CI logs anym…

Did you have your types root set to `node_modules` in your `tsconfig.json`?

Re: Using TypeScript with React

#38

Post by towndrunk »

bauerd wrote: post #36

I'm currently trying to revive a 2yrs old codebase written with TypeScript/React/Redux. I made the capital error of not checking in node_modules apparently or pinning versions (ie using yarn or npm shrinkwrap), as I now get tons and tons of type errors from dependencies on build. Problem seems to be that all the @types packages are somehow out of sync/broken/hell I don't know. I also don't have access to CI logs anym…

Is there a package-lock.json checked in? If you can get the earliest version you may be able to find the versions there.

Re: Using TypeScript with React

#39

Post by kabes »

towndrunk wrote: post #38
bauerd wrote: post #36

I'm currently trying to revive a 2yrs old codebase written with TypeScript/React/Redux. I made the capital error of not checking in node_modules apparently or pinning versions (ie using yarn or npm shrinkwrap), as I now get tons and tons of type errors from dependencies on build. Problem seems to be that all the @types packages are somehow out of sync/broken/hell I don't know. I also don't have access to CI logs anym…

Is there a package-lock.json checked in? If you can get the earliest version you may be able to find the versions there.

Probably not, since package lock files were only introduced 2 years ago.

Re: Using TypeScript with React

#40

Post by krzkaczor »

h0h0h0h0111 wrote: post #22

I've been writing Typescript with React for quite a while now and these are my feelings so far: - Typescript type system is pretty awesome, and allows the expression of some things really elegantly; in particular, string literal types are quite cool for component props that feel "htmly", union and intersection types are great for making reusable/generic components and Partial is cool for making typesafe component sta…

> - using `any` nearly always comes back to bite you as you trick yourself into feeling typesafe

This. I was so frustrated with this point that I created a tool for automatic tracking type coverage on PRs called TypeCov.

https://github.com/codechecks/typecov

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