[vanwalj]

Here are some examples: TS: https://www.typescriptlang.org/play/#src=type%20TA%20%3D%20%... Flow: https://flow.org/try/#0PQKgBAAgZgNg9gdzCYAoVAXAngBwKZgCSAgmA...

With Typescript, you have to write custom Type Guards functions, whereas Flow is smart enough to infer type

[johnfn]

If you use discriminated union types - e.g. give them both a type key which is a unique string, then you don't need type guards as typescript is smart enough to understand that checking the type key does the type discrimination.

[vanwalj]

Sure, but you don't always have control over an external module or service, and it still something flow is better at

[johnfn]

Yeah, that's true. I don't know why you've been downvoted. You have a legitimate answer.