onSuccess and onFailure

These methods allow you to perform side effects based on the success or failure of a Result. They are useful for logging, notifications, or any other action that should occur without altering the result itself.

declare const result: Result<string, Error>;

const nextResult = result
  .onSuccess((value) => console.log("Operation succeeded with value", value))
  .onFailure((error) => console.error("Operation failed with error", error));

INFO

Regardless of what the callback returns, the original Result is returned unchanged.

WARNING

These methods do not catch any thrown exceptions. If you feel the need to capture any errors inside the callback, it may be a smell that you should use mapCatching instead.

INFO

If you need to perform a side effect for a specific case, it is recommended to use a nesting approach as shown below:

declare const result: Result<string, ErrorA>;
declare const otherResult: Result<string, ErrorA>;

const nextResult = result.map(() => 
  otherResult.onSuccess((value) => console.log("Other operation succeeded with value", value))
);