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Comment by jadayesnaamsi | Hacker News Reader

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jadayesnaamsi

It is the first time I see that "hook" pattern in a Go API backend: `hook.Hook` and `hook.TaggedHook`.

Where does it come from?

Why is it useful here?

What are the alternatives? Advantages/Drawbacks?

Is there an article somewhere, outside of the Pocketbase docs, presenting that pattern?

- https://github.com/pocketbase/pocketbase/blob/master/core/ap...

- https://github.com/pocketbase/pocketbase/tree/master/tools/h...

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This just looks like the "Event Bus" [1] [2] [3] pattern, this is not the one from the React world if you were thinking about that. Hooks here are just the following, the "Hook" is just a collection of event handlers.

    type Handler[T any] func(e T) error

    type handlerPair[T any] struct {
        id      string
        handler Handler[T]
    }

    type Hook[T any] struct {
        mux      sync.RWMutex
        handlers []*handlerPair[T]
    }

It's very useful when you want to make an easily extensible library/framework/application, as you can see in pocketbase/core/app.go you can register handlers for various things that can happen.

[1]: https://en.wikipedia.org/wiki/Event-driven_programming

[2]: https://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_patt...

[3]: https://en.wikipedia.org/wiki/Observer_pattern

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