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> And the React ecosystem tends to either lack typings or provide poor/broken typings. React integrates really well with flow[1] (which is not surprising becau

by stymaar 10y ago

> And the React ecosystem tends to either lack typings or provide poor/broken typings. React integrates really well with flow[1] (which is not surprising because they're both developed at Facebook) and in my experience flow's typesystem is more powerful (OCaml inspired) than TypeScript one (C# inspired): - non-nullable types by default is a big deal (they added support for non-nullable types in TypeScript 2, but enabling it with `--strictNullChecks` is a breaking change, so I don't think many users have done the switch). - the type checker is sometimes not strict enough to be sound [2]. [1] : https://flowtype.org https://flowtype.org [2] : http://djcordhose.github.io/flow-vs-typescript/2016_hhjs.html#/21 http://djcordhose.github.io/flow-vs-typescript/2016_hhjs.htm...

voidr 10y ago
> React integrates really well with flow[1] (which is not surprising because they're both developed at Facebook) It can integrate just as well with TypeScript. > flow's typesystem is more powerful (OCaml inspired) It lacks access control for class properties/methods, I wouldn't call that powerful. https://flow.org/en/docs/types/classes/ https://flow.org/en/docs/types/classes/
- stymaar 10y ago
  > It lacks access control for class properties/methods, I wouldn't call that powerful. You mean `private` and such ? Well JavaScript don't support taht either yet, and flow is a type-system for JavaScript, it's not a new language on its own. About the «powerful» word: Flow has had an algebraic data type (ADT) from the beginning, the kind of type system you'd find in functional programming languages, whereas TypeScript has and Object-Oriented type-system (à la Java or C#). ADT are usually considered «more powerful» since it offers more ways to write logical invariants in your code. The recent versions of TypeScript tries to retro-fit some features of ADTs into it, like non-nullable types or sum types, but it's a bit hacky IHMO[1]. [1]: https://www.typescriptlang.org/docs/handbook/advanced-types.html#discriminated-unions https://www.typescriptlang.org/docs/handbook/advanced-types....
  - addicted 10y ago
    Typescript has had Discriminated Unions as long as I can remember (pre 1.0). Why do you think they've been hacked in?
wereHamster 10y ago
> React integrates really well with flow No. The flow types around React are really poor. There are many things flow can't represent. The types are 'private' (all types in flow with a dollar in the name are private, not publicly supported. eg. React$Element). The implementation of React$Element is hardwired into flow. If you have to include specific support for libraries it tells a lot about the expressiveness of the underlying type system, doesn't it? There is no way to represent a react node, fragment etc. Properly typing children of a react component is impossible.

by stymaar 10y ago

voidr 10y ago

> React integrates really well with flow[1] (which is not surprising because they're both developed at Facebook) It can integrate just as well with TypeScript. > flow's typesystem is more powerful (OCaml inspired) It lacks access control for class properties/methods, I wouldn't call that powerful. https://flow.org/en/docs/types/classes/ https://flow.org/en/docs/types/classes/

stymaar 10y ago
> It lacks access control for class properties/methods, I wouldn't call that powerful. You mean `private` and such ? Well JavaScript don't support taht either yet, and flow is a type-system for JavaScript, it's not a new language on its own. About the «powerful» word: Flow has had an algebraic data type (ADT) from the beginning, the kind of type system you'd find in functional programming languages, whereas TypeScript has and Object-Oriented type-system (à la Java or C#). ADT are usually considered «more powerful» since it offers more ways to write logical invariants in your code. The recent versions of TypeScript tries to retro-fit some features of ADTs into it, like non-nullable types or sum types, but it's a bit hacky IHMO[1]. [1]: https://www.typescriptlang.org/docs/handbook/advanced-types.html#discriminated-unions https://www.typescriptlang.org/docs/handbook/advanced-types....
- addicted 10y ago
  Typescript has had Discriminated Unions as long as I can remember (pre 1.0). Why do you think they've been hacked in?

wereHamster 10y ago

> React integrates really well with flow No. The flow types around React are really poor. There are many things flow can't represent. The types are 'private' (all types in flow with a dollar in the name are private, not publicly supported. eg. React$Element). The implementation of React$Element is hardwired into flow. If you have to include specific support for libraries it tells a lot about the expressiveness of the underlying type system, doesn't it? There is no way to represent a react node, fragment etc. Properly typing children of a react component is impossible.