5 replies

Combining Option and Effect without Errors

Hello!

First of all - thanks for the library, I really enjoy working with it!
For the past few weeks I have been giving effects a try. Everything went smoothly up until I tried to connect Option with an Effect.
This is the simplified code snippet I have:

const anonymousToken = (exists: boolean) => {
  if (exists) {
    return Option.some(JSON.stringify({ name: 'My Name' }));
  }
  return Option.none();
};

const decodeToken = (token: string) => {
  return Effect.promise(() => Promise.resolve(JSON.parse(token)));
};

const apiCall = (token: { name: string }) => {
  return Effect.promise(() => Promise.resolve({ success: true }));
};

const result = await Effect.runPromise(
  anonymousToken(false).pipe(
    Effect.flatMap(decodeToken),
    Effect.flatMap(apiCall)
  )
);

const anonymousToken = (exists: boolean) => {
  if (exists) {
    return Option.some(JSON.stringify({ name: 'My Name' }));
  }
  return Option.none();
};

const decodeToken = (token: string) => {
  return Effect.promise(() => Promise.resolve(JSON.parse(token)));
};

const apiCall = (token: { name: string }) => {
  return Effect.promise(() => Promise.resolve({ success: true }));
};

const result = await Effect.runPromise(
  anonymousToken(false).pipe(
    Effect.flatMap(decodeToken),
    Effect.flatMap(apiCall)
  )
);

The idea behind is to use Option data structure for returning a anonymous cookie value from the request. This value is optional, therefore the Option. When the option is specified - I want to continue the pipeline and it is working as expected. However when the cookie is not present (Option.none) - I get an error.
So here are my questions:
* Is there any way I could make it work without capturing "NoSuchElementException" ?
* In general, I would expect the pipeline not to be executed, as the Option value is set to none.
* Maybe I'm not approaching the problem in the correct way? Maybe I should change the logic instead? If so - how should I do it?

const anonymousToken = (exists: boolean) => {
  if (exists) {
    return Option.some(JSON.stringify({ name: 'My Name' }));
  }
  return Option.none();
};

const decodeToken = (token: string) => {
  return Effect.promise(() => Promise.resolve(JSON.parse(token)));
};

const apiCall = (token: { name: string }) => {
  return Effect.promise(() => Promise.resolve({ success: true }));
};

const result = await Effect.runPromise(
  anonymousToken(false).pipe(
    Effect.flatMap(decodeToken),
    Effect.flatMap(apiCall)
  )
);

const anonymousToken = (exists: boolean) => {
  if (exists) {
    return Option.some(JSON.stringify({ name: 'My Name' }));
  }
  return Option.none();
};

const decodeToken = (token: string) => {
  return Effect.promise(() => Promise.resolve(JSON.parse(token)));
};

const apiCall = (token: { name: string }) => {
  return Effect.promise(() => Promise.resolve({ success: true }));
};

const result = await Effect.runPromise(
  anonymousToken(false).pipe(
    Effect.flatMap(decodeToken),
    Effect.flatMap(apiCall)
  )
);

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