js-proposal-algebraic-effects VS errors

I have to admit: you're perfectly right here. React of course always relied on mutable state in it's implementation – just so we don't have to. I derailed a lot here to keep this funny thread going ;) I'm still not with you on your definition of "functional", since you treated it synonymously with "purely functional". Functional means just made by applying and composing functions, and react UI is created exactly like that. There is an awesome algebraic effects proposal[1], which will hopefully will be added to JavaScript one day, then react will make use of it to become purely functional.

1: https://github.com/macabeus/js-proposal-algebraic-effects

Super interesting, there is a proposal to add this to JavaScript and several languages that use this, unison, koka & eff. I had no idea this was even a thing!

Ok I was wrongly assuming that panic was expecting an error type, in fact it's an interface{}.

> Your use of exceptions for flow control (i.e. goto) is considered harmful

Exceptions are a way to delegate error handling to the caller by giving them informations about the unexpected behavior. It implies that the expected behavior is the "happy path" (everything went well) and any deviations (errors) is unexpected.

This is far from a goto because you can have `try/finally` blocks without catch (or defer in golang).

Also, exceptions are just a kind of algebraic effects that do not resume. There was a proposal to JS for this: https://github.com/macabeus/js-proposal-algebraic-effects

This is also easier to test. assertRaises(ErrorType, func() { code... })

Almost every Go library I've seen just return an error (which is just a string), you'd need to parse it to assert that the correct error is returned in special conditions.

Can you explain why we should this over https://github.com/pkg/errors?

The pkg/errors package offers some nice add-ons for easier error handling. Too bad it was put into maintenance mode pending whatever changes/improvements are coming in Go 2.

I can't figure out the issue so here for some help, I am using `neovim/nvim-lspconfig` my `gopls` doesn't recognise external paths such as `github.com/pkg/errors` , it throws error`could not import github.com/pkg/errors (cannot find package "github.com/pkg/errors" in any of /usr/local/go/src/github.com/pkg/errors (from $GOROOT) /Users/ra compiler (BrokenImport)\`

Also - there are some error handling utils that allow you to wrap errors before passing: https://github.com/pkg/errors

Should've been something like errors.Newf("failed to foofoo %s", foo) instead and preferably never invent %w but have some controlled way to wrap like errors.Wrapf(err, "failed to foofoo %s", foo) that was in ye olde github.com/pkg/errors.

Prefer using errors.Wrap and errors.Wrapf from https://github.com/pkg/errors . It's frozen because they don't want to add features, waiting for a re-write of error handling in Go2.

Im using zerolog and in order to get the stack trace for my error I have to wrap my error in errors.Wrap from "github.com/pkg/errors".

And for "real programs" you can use https://github.com/pkg/errors (if you want stack traces)