One-Way Data Flow (in Ruby)

A short introduction to one-way data flow and Rbdux, a Ruby library to help implement it.

Transcript

1. Joshua Tompkins | @jtompkinsx ONE-WAY DATA FLOW REDUX-STYLE (IN )
2. *cough* left-pad.js *cough*
3. http://facebook.github.io/flux
4. “Flux is an architecture for creating data layers in JavaScript applications. It was designed at Facebook along with the React view library. It places a focus on creating explicit and understandable update paths for your application's data, which makes tracing changes during development simpler and makes bugs easier to track down and fix.”
5. Flux is about managing state. If your application state is easy to reason about, your application is easy to reason about.
7. http://fluxxor.com/what-is-flux.html
8. “computers. . . have very large numbers of states. This makes conceiving, describing, and testing them hard. Software systems have orders-of-magnitude more states than computers do.” FRED BROOKS 1986
9. Managing state is REALLY FREAKING HARD. FRED BROOKS 2016 (sort of)
10. http://redux.js.org
11. THE THREE PRINCIPLES OF REDUX
12. Single source of truth.
13. State is immutable.
14. Changes are made with pure functions.
15. store reducer new state app action
16. DATA BEHAVIOR APPLICATIONS + = STATE ACTIONS & REDUCERS
18. Javascript is so not omakase. DHH DEFINITELY NOT 2016
19. dux github.com/jtompkins/rbdux
20. store reducer new state app action
21. Rbdux::Action.define('new_todo')
22. NewTodoAction.empty NewTodoAction.with_payload('Try out Redux!') NewTodoAction.with_error('An error')
23. Rbdux::Store.with_state(todos: [])
24. Rbdux::Store.reduce(NewTodoAction) do |state, action| new_state = state.dup()[:todos].add(action.payload) new_state end
25. Rbdux::Store.reduce(NewTodoAction, :todos) do |state, action| state.dup << action.payload end
26. Rbdux::Store.subscribe { do_a_thing }
27. action = NewTodoAction .with_payload('Add a new todo.') Rbdux::Store.dispatch(action)
28. { todos: ['Add a new todo.'] }
29. it 'adds a todo item' do a = NewTodoAction.with_payload('test') Rbdux::Store.dispatch(a) expect(Rbdux::Store.state) .to eq({ todos: ['test'] }) end
30. EXTERNAL DATA CALLS DISPATCH_INTERCEPTOR MIDDLEWARE
31. store reducer new state app action external data?
32. Rbdux::Store.before do |store, action| puts action.inspect end
33. Rbdux::Store.after do |old_state, new_state, action| puts new_state end
34. require ‘net/http' Rbdux::Store.before(&Rbdux::Middleware .dispatch_interceptor) Rbdux::Action.define('get_data') do |store, action| uri = URI('http://example.com/todos') data = Net::HTTP.get(uri) DataRetrievedAction.with_payload(data) end Rbdux::Action.define('data_retrieved')
35. IMMUTABLE STORE DATA USER-DEFINED MERGE + IMMUTABLE DATA STRUCTURES
36. Rbdux::Store.when_merging do |old_state, new_state, state_key| merge_some_stuff!(old_state, new_state) end
37. IS RBDUX SOMETHING I SHOULD USE?
38. NO
39. Okay, maybe. (but still probably not)
40. FUTURE WORK Thread Safety! Transaction Logging Fully-Replaceable Store
41. THANKS FOR LISTENING! github.com/jtompkins/rbdux @jtompkinsx