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useRef in store.subscribe, re-render

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const Dashboard : React . FC = () => { const store = createStore ( countReducer ) const divRef = useRef < HTMLDivElement >( null ); store . subscribe (() => { const state = store . getState () if ( divRef . current ) divRef . current . innerText = `this is cool, another listener: ${ state . count } ` ; }) return ( ... < button onClick = { () => store . dispatch ({ type : ActionType . INCREMENT }) } > add </ button > < button onClick = { () => store . dispatch ({ type : ActionType . DECREMENT }) } > minus </ button > < div ref = { divRef } > 0 </ div > ... ) } Re-Render: const count = useRef ( 0 ) ; useEffect ( ( ) => { count . current = count . current + 1 ; } ) ; return ( < > < input type = " text " value = { inputValue } onChange = { ( e ) => setInputValue ( e . target . value ) } /...
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setup prettier / eslint for create-react-app typescript

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1. npm i -D prettier  2. create .prettierrc.json { "trailingComma": "all", "tabWidth": 2, "singleQuote": true, "jsxBracketSameLine": true,    "semi": false } 3. npm i -D eslint-config-prettier 4. in package.json, add this: "eslintConfig": { "extends": [ "react-app", "react-app/jest", "prettier" ] }, 5. install extension in VS Code Prettier extension
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Big-Oh (O) Notation, and sorting in Javascript

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Asymptotic notations are classified into three types: Worst case time complexity : It is a function defined as a result of a maximum number of steps taken on any instance of size n. It is usually expressed in  Big O notation . Average case time complexity : It is a function defined as a result of the average number of steps taken on any instance of size n. It is usually expressed in  Big theta notation . Best case time complexity : It is a function defined as a result of the minimum number of steps taken on any instance of size n. It is usually expressed in  Big omega notation . Space complexity : It is a function defined as a result of additional memory space needed to carry out the algorithm. It is usually expressed in  Big O notation . Big-Oh (O) notation Big Omega ( Ω ) notation Big Theta ( Θ ) notation Default sort() in JavaScript uses  insertion sort  by  V8 Engine of Chrome  and  Merge sort  by  Mozilla Firefox  and...
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