Effect CommunityEC
Effect Community•3y ago•
5 replies
Jérôme MARTIN

Error in Effect generator

Hi there,

I am using an effect generator and, at some point I need, depending on a test, to escape with an error.
To do that, I yield an error.
It works but the compiler does not know that the code after the yield will never be executed. So type narrowing does not work.
Instead of yielding an error, I tried to return it, to return a left, to return a failed effect. But the contents always go into the success channel and not into the error channel.
Adding an else or returning void adds and undefined in the success channel.

Here's what my code looks like:
const e = Effect.gen(function* ($) {
    ...
    
    if (supplier === undefined) yield* $(new EntryError('Supplier not found'));
        ...
        // raises a warning because supplier might be undefined
        const t = supplier.name;
    ...

    return { entries: [entry1, entry2], nextEntryCursor, nextDocCursors };
});

Is there a trick?

Thanks in advance for your help.
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