\n ![\"react-atom](\"https://document-export.canva.com/DADKGVfSlSY/19/preview/0001-541240887.png\"\n)
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\n User {userId} has selected {color}\n
\n {/* `useAtom` hook will trigger a re-render on `swap` */}\n \n\n `Atom.of`, `useAtom`, and `swap` will cover the vast majority of use cases.\n\n
\n Reducers? Actions? Thunks? Sagas? Nope, just `swap(atom, state => newState)`. \n\n
\n The\nuseAtomhook accepts an optionalselectfunction that lets components subscribe to computed state. That means the component will only re-render when the value returned fromselectchanges.\n
React.useState doesn't play nice with React.memo\n \n\nuseStateis cool until you realize that in most cases it forces you to pass new function instances through props on every render because you usually need to wrap thesetStatefunction in another function. That makes it hard to take advantage ofReact.memo. For example:\n---\n\n```jsx\nfunction Awkwardddd(props) {\n const [name, setName] = useState(\"\");\n const [bigState, setBigState] = useState({ ...useYourImagination });\n\n const updateName = evt => setName(evt.target.value);\n const handleDidComplete = val => setBigState({ ...bigState, inner: val });\n\n return (\n <>\n \n\n \n );\n}\n```\n\nEvery time `input` fires `onChange`, `ExpensiveButMemoized` has to re-render because `handleDidComplete` is not strictly equal (===) to the last instance passed down.\n\nThe React docs admit this is awkward and [suggest using Context to work around it](https://reactjs.org/docs/hooks-faq.html#how-to-avoid-passing-callbacks-down), because [the alternative is super convoluted](https://reactjs.org/docs/hooks-faq.html#how-to-read-an-often-changing-value-from-usecallback).\n\nWith `react-atom`, this problem doesn't even exist. You can define your update functions outside the component so they are referentially stable across renders.\n\n```jsx\nconst state = Atom.of({ name, bigState: { ...useYourImagination } });\n\nconst updateName = ({ target }) => swap(state, prev => ({ ...prev, name: target.value }));\n\nconst handleDidComplete = val =>\n swap(state, prev => ({\n ...prev,\n bigState: { ...prev.bigState, inner: val }\n }));\n\nfunction SoSmoooooth(props) {\n const { name, bigState } = useAtom(state);\n\n return (\n <>\n \n \n \n );\n}\n```\n\n
\n react-atom is written in TypeScript so that every release is published with correct, high quality typings.\n \n\n Hooks will make\nclasscomponents and their kind (higher-order components, render-prop components, and function-as-child components) obsolete.react-atommakes it easy to manage shared state with just function components and hooks.\n
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