Fixes

• Fixes cases where exceptions thrown inside AsyncResult's were trapped, which resulted in unhandled exceptions.

Minor changes

• adds toTuple() to both the Result and AsyncResult class, allowing you to destructure a result and use TypeScript's narrowing capabilities (instead of having to check with isOk() and isError()).

declare const result: Result<number, ErrorA>;

const [value, error] = result.toTuple();

if (error) {
  // error is ErrorA
} else {
  // at this point the value must be a number
}

// or 'Go-style'
if (error === null) {
 // do something with the value
}

Breaking changes

• #2 Throws the error directly instead of wrapping the encapsulated error in an additional error when using getOrThrow()

Fixes

• Fixes issue where AsyncResult's onSuccess and onFailure did not await promises well, resulting in 'dangling' promises

Minor changes

• added mapError method to both the Result and AsyncResult instances, which allows you to transform the encapsulated error of a failed result (#9 )
• added an additional parameter to the mapCatching method (transformErrorFn) which allows you to transform the potential error caught while transforming. (#9)

Thanks @derkbell for suggesting this improvement and helping out with a solution!

Fixes

• Moves the default export condition to last position in package.json. See #6.

Thanks @trombipeti for helping and pointing this out!

• Result.safe() now accepts a error-class as parameter:

class CustomError() {}
const result = Result.safe(CustomError, () => 2 * 2);

• Result.safe() now accepts a callback which returns another Result an will merge both Results:

class CustomError() {}
function doStuff(): Result<CustomError, number> {}
const result = Result.safe(() => doStuff()); // Result<Error | CustomError, number>

• Result#map() now accepts a callback that returns another result (flat-map) or a callback that transforms the value directly:

function doStuff(): Result<CustomError, number> {}

const result = doStuff().map(num => num * 2); // Result<Error | CustomError, number>

Added Result.forward()

Initial release!