Discussion on: Type-Safe Error Handling In TypeScript

Would be great if typescript allows pattern matching, then you’ll do

with(result){
   Err(e) => console.log(“error!”);
   Ok(value) => console.log(value);
}

One way I was able to deal with 'callback hell':

• Add functional helpers like map, mapErr, biMap (match), flatMap (andThen) etc that can work with both Result... and Promise<Result...
• Add .pipe function on Ok and Err, and Promise, pretty much as implemented in rxjs: accept to pass N amount of continuation functions with signature: (previous) => next

so now I can:

await getSomeRecordsAsync() // => Promise<Result<SomeRecords, SomeError[]>>
  .pipe(
    map(someRecords => someRecords.map(x => x.someField).join(", ")), // => Promise<Result<string, SomeError[]>>
    mapErr(err => err.map(x => x.message).join(", ")), // => Promise<Result<string, string>>
    flatMap(saveStringAsync), // => Promise<Result<void, someError>>
    // etc
  )

(with full Typescript typing support btw!)

Thinking about releasing it to GitHub and npm at some point :)

My post, framework and sample just landed dev.to/patroza/result-composition-...