Troubleshooting

This page covers common issues you might encounter when using @deessejs/fp and how to solve them.

Type Errors

AsyncResult Issues

Maybe Issues

Error System Issues

Import Issues

General Advice

If you're still having issues after trying these solutions, please open an issue on GitHub with a minimal reproduction. This helps us improve the documentation and library.

Getting Help

Check the FAQ for common questions
Look at the Reference documentation for API details
Search existing GitHub issues for similar problems

Type Errors

TypeScript is not narrowing the type after isOk()

Error type is inferred as 'unknown'

FlatMap is not chaining correctly

AsyncResult Issues

AsyncResult methods require await

fromPromise rejects with non-Error values

all() throws on first error

Maybe Issues

some(null) creates a Some with null value

Chained property access returns Maybe<Maybe<T>>

Error System Issues

Zod validation errors have strange messages

Error cause chain is not showing

Import Issues

Cannot find module '@deessejs/fp'

ESM import errors in CommonJS projects

General Advice

Getting Help

On this page