Flow

SWC has added support for Flow: swc.rs/docs/usage/flow

Flow now supports Mapped Types, inspired by TypeScript. Read more about them in our new blog post: medium.com/flow-type/anno…

@naman34 As we roll out React 19 internally we will not need to change any product code to get rid of forwardRef calls. We'll only need to change the Component Syntax transform. One less thing for developers to think about!

Little known fact. The new component syntax also lets you treat “ref” like a prop. As if React 19 was already here!

The render types section of the blog post doesn't even go all that in depth. This is contrived for the sake of conciseness but really pay attention to what this code is expressing and understand how buck wild it is that we can express this with complete type safety!

@tomus_sherman Yes, mutating methods are significantly more difficult to detect than direct property mutations. Doing this soundly might be prohibitively difficult to adopt in a large codebase, so we're looking into multiple options. This is an active area of investigation for us!

@flowtype Readonly props doesn't protect against mutable methods right, any plans to fix that?

We added new language features to Flow for writing React. Learn about our new Component Syntax: medium.com/flow-type/anno…

Flow now supports Type Guards (functions that can be used to narrow a type)! Unlike @TypeScript, we run checks on the body of the function to catch some invalid definitions. medium.com/flow-type/anno…

@flowtype is now releasing some TS features before TS! xD github.com/facebook/flow/…: > Flow now supports the same NoInfer intrinsic that will be available in TypeScript 5.4.

Flow now supports Conditional Types, which allow you to choose an output type based on an input type - like a ternary expression for types: medium.com/flow-type/anno…

Flow now uses "as" syntax for type-casting, and unlike TypeScript it's safe: medium.com/flow-type/new-…

We’ve refreshed our documentation (flow.org/en/docs/) , and added the ability to configure options and lints in Try Flow (flow.org/try/)! medium.com/flow-type/5da5… Website is now built with @docusaurus

Announcing 5 new Flow tuple type features: medium.com/flow-type/anno…

Flow can now detect unused Promises: medium.com/flow-type/flow…

Announcing Partial & Required Flow utility types + catch annotations: medium.com/flow-type/anno…

We're making exact object types the default in Flow: medium.com/flow-type/exac…

We just announced a new type checking mode that will make Flow's inference much more predictable and reliable. Check out our latest blog post for more info and instructions for upgrading to the new mode. medium.com/flow-type/loca…

Improved handling of the empty object in Flow: medium.com/flow-type/impr…

We just announced a new language enforcement flag to help prepare your codebase for Local Type Inference. Check out our latest blog post for more info and instructions for enabling that flag. medium.com/flow-type/requ…

We just released a new language rule that'll make Flow's inference much more predictable. Check out our latest blog post for more info and instructions for upgrading to that new inference mode. medium.com/flow-type/new-…