The state of the state: React state management in 2019

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THE State of the state: React State Management IN 2019 @YTHECOMBINATOR

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1PUB/42m

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Bring me that!

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"""

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal REDUX-ACT IMMER

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https://github.com/GantMan/ReactStateMuseum

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"Javascript Fatigue" by Eric Cle!"ons

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HAS THE SO-CALLED JAVASCRIPT FATIGUE REACHED (REACT) STATE MANAGEMENT?

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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Tldr; Ofﬂoad store management logic to a separate web worker.

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https://github.com/developit/stockroom

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DEMO

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HIGHLIGHTS: ↝ + Performance ↝ Good for CPU-bound store mutations

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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Tldr; Declaratively describing the behaviour of your application

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FEATURING: ↝ A list of states ↝ One initial state ↝ A list of events that trigger transitions

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DEMO

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HIGHLIGHTS: ↝ Preciseness of specs ↝ Correctness of code ↝ Less unimportant state / Less if clauses ↝ Leverage knowledge from non-coders too

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CONS: ↝ Surely an overkill for super simple components ↝ Lack of familiarity from developers and designers ↝ Small ecosystem

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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Tldr; Combine your local and remote state management

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Key Concepts: ↝ DEFAULTS: Your base state. What you start with. ↝ RESOLVERS: Where all the magic happens to retrieve and update your local data in the Apollo cache.

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DEMO

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HIGHLIGHTS: ↝ Getting Apollo set up just for state management can be a bit of work ↝ A natural way of querying and mutating state

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cons: ↝ Surely an overkill for apps that don't heavily depend on remote state

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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Tldr; Redux best practices without the boilerplate.

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https://github.com/jamiebuilds/unstated

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https://github.com/pedronauck/reworm #

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import React from 'react' import { Provider, create } from 'reworm' const { set, get } = create({ name: 'John' }) class App extends React.Component { componentDidMount() { set(prev $% ({ name: 'Peter' + prev.name })) } render() { return (

{get(s $% s.name)}

) } }

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HIGHLIGHTS: ↝ - Boilerplate ↝ + Simplicity

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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Tldr; Recreate Redux in our React app without actually installing redux and react-redux

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Key Concepts: ↝ CONTEXT: Provides a way to pass data through the component tree without having to pass props down manually at every level. ↝ HOOKS: Let you use state and other React features without writing a class

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DEMO

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HIGHLIGHTS: ↝ Less boilerplate than redux itself ↝ No third-party dependencies

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cons: ↝ Still carries some of redux boilerplate ↝ You might face a few perf issues

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Split contexts that don't change together function Button() { let theme = useContext(ThemeContext); &' The rest of your rendering logic return ; }

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Split your component in two, put memo in between function Button() { let appContextValue = useContext(AppContext); let theme = appContextValue.theme; &' Your "selector" return } const ThemedButton = memo(({ theme }) $% { &' The rest of your rendering logic return ; });

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One component with useMemo inside function Button() { let appContextValue = useContext(AppContext); let theme = appContextValue.theme; &' Your "selector" return useMemo(() $% { &' The rest of your rendering logic return ; }, [theme]) }

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HAS THE SO-CALLED JAVASCRIPT FATIGUE REACHED (REACT) STATE MANAGEMENT?

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HAS THE SO-CALLED JAVASCRIPT FATIGUE REACHED (REACT) STATE MANAGEMENT? Maybe! BUT SO HAS THE VANILLA WAY OF DOING THINGS!

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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https://github.com/pauldijou/redux-act

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const serializeTodo = createAction('SERIALIZE_TODO'); serializeTodo(1); &' return { type: 'SERIALIZE_TODO', payload: 1 }

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const loading = createReducer({}, initialState.loading) .on(actions.fetch, () $% true) .on(actions.setQuery, () $% true) const ids = createReducer({}, initialState.ids) .on(actions.setIds, (state, payload) $% [&&.payload]) .on(actions.delete, (state, payload) $% { return [&&.state.filter((id) $% id ))* payload)]; });

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HIGHLIGHTS: ↝ Less boilerplate than plain redux ↝ Piping syntax for reducers

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Apollo link state Unstated Stockroom alfa MOBX setState() Redux CONTEXT HOOKS reworm Relay React Automata freactal IMMER REDUX-ACT

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⚠ INTERMISSION ⚠ Immutability

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WHY: ↝ - Breakable ↝ + Debuggable ↝ + Performant

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WHY: ↝ - Breakable ↝ + Debuggable ↝ + Performant

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WHY: ↝ - Breakable ↝ + Debuggable ↝ + Performant

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WHY: ↝ - Breakable ↝ + Debuggable ↝ + Performant

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WHY: ↝ - Breakable ↝ + Debuggable ↝ + Performant Full Reconciliation REACT Reconciliation REACT + IMMUTABLE

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WHY: ↝ - Breakable ↝ + Debuggable ↝ + Performant Full Reconciliation O(N^3) REACT Reconciliation O(N) REACT + IMMUTABLE O(LOGN)

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https://github.com/immutable-js/immutable-js

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~300

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https://github.com/kolodny/immutability-helper

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import update from "i!"utability-helper" const reducer = (state, action) $% { switch (action.type) { case ADD_TAG: return update(state, { [action.id]: { tags: { $push: [action.tag] } } }) default: return state } }

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https://github.com/immerjs/immer

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const map1 = { foo: 1, bar: 2 } const map2 = I!"utable.Map(map1) const { foo, bar } = map2 console.log(foo) &' undefined console.log(bar) &' undefined

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const map1 = { foo: 1, bar: 2 } const map2 = produce(map1, draft $% { draft.foo += 10 }) const { foo, bar } = map2 console.log(foo) &' 11 console.log(map1.bar ++, bar) &' true

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exposes a single default function that does all the work const map1 = { foo: 1, bar: 2 } const map2 = produce(map1, draft $% { draft.foo += 10 }) const { foo, bar } = map2 console.log(foo) &' 11 console.log(map1.bar ++, bar) &' true

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const map1 = { foo: 1, bar: 2 } const map2 = produce(map1, draft $% { draft.foo += 10 }) const { foo, bar } = map2 console.log(foo) &' 11 console.log(map1.bar ++, bar) &' true apply all your changes to a temporarily draft State, which is a proxy of the currentState.

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your objects and arrays are really JavaScript objects and arrays, so you can do everything you would normally do const map1 = { foo: 1, bar: 2 } const map2 = produce(map1, draft $% { draft.foo += 10 }) const { foo, bar } = map2 console.log(foo) &' 11 console.log(map1.bar ++, bar) &' true

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&' add a tag to a todo { &&.state, [action.id]: { &&.state[action.id], tags: [ &&.state[action.id].tags, action.tag ] } } &' add a tag to a todo state[action.id].tags.push(action.tag)

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ALSO: ↝ ES5 Fallback ↝ Strongly typed ↝ Small (4KB) ↝ Currying

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ALSO: ↝ Fast Auto freezing ↝ Equivalent perf to ImmutableJS ↝ Supports hooks!

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⚠ ❌ ❌ ⚠

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~ senior software engineer, Front-End @beakyn ~ @ythecombinator on the webs ~ addicted to emojis, memes and beer