Question

What are the current best practices?

Answer

To grasp best practices:

1. Read through the re-frame documentation.
2. Review example projects, like this RealWorld example. The Resources doc provides further examples.

Keep in mind, best practices evolve over time. Here are some of the more recent ideas.

Use Namespaced Keywords

In the interests of minimalism, the docs don't use namespaced keywords for ids (event ids, subscription ids, etc), but in prectice you should.

You can use either synthetic or real namespaces in your ids, but some experienced re-framers claim you should only use real namespaces. I remain unconvinced. Shrug.

Tip: tooling like clojure-lsp can help you to navigate to where an event id or subsription id is registered.

Structuring app-db

While using app-db as a simple map works well in many situations, if you want more structure, consider using a library like doxa or relic.

Use the :fx effect

While event handlers can return a map of arbitrary effects, it is now recommended that they only return a map containing two standard keys :db and :fx. Learn more here and here.

Compose Event Handlers

Event handlers can be composed of other functions through the use of the :db / :fx effect pattern, which is described here

Avoid Placeful Events

Originally, it was recommended that events be a vector like this [:some-event-id arg1 arg2]. This works reasonably for simple cases, but it does introduce fragility for more complex use cases due to the lnherent "placefulness" of vectors.

A better practice is to encapsulate the "args" into a single map: [:some-event-id {:x arg1 :another arg2}]

And then to optionally use the unwrap middleware on the associated event handlers. See here