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I'm reading that they recommend the use of the Hook useReducer when dealing with a complex state. But my doubt starts from the following scheme: But my doubt starts from the following scheme: Using React + Typescript , suppose I have a state with several fields (I'll give an example with classes):
Get to know useReducer. React docs. useReducer is usually preferable to useState when you have complex state logic that involves multiple sub-values or when the next state depends on the previous one. useReducer also lets you optimize performance for components that trigger deep updates because you can pass dispatch down instead of callbacks.
Nov 25, 2019 · /* Here is the magic. The `initialState` pass to * `useReducer` as second argument will be hook * here to init the real `initialState` as return * of this function */ const countInitializer = initialState => { return { count: initialState, otherProp: 0 }; }; const countReducer = state => state; // Dummy reducer const App = => { const [countState /*, countDispatch */] = React.useReducer(countReducer, 2, countInitializer); // Note the `countState` will be initialized state direct on first ...
Feb 7, 2019 · useReducer's state is local to a single component - if you wanted to use this state throughout your app, you'd need to pass it (and/or the dispatch function) down via the props. It's effectively just a more structured version of useState - in fact, useState is implemented using useReducer under the hood !
May 16, 2020 · My goal is to implement a React controlled input using the useReducer hook. Inside the reducer I need the event.target.value and event.target.selectionStart to get the current value and caret posi...
Feb 12, 2019 · @ecoe, no useReducer is not functionally equivalent to useCallback. useCallback is for memoization of functions whereas useReducer is used to store and update states. The dispatch returned by useReducer doesn't change on each render and hence can pass it to child components applying memoization –
Jul 31, 2019 · If you seek an Redux-like implementation of combineReducers for useReducer, also have a look at Lauri's answer, though I recommend to use a different implementation for most cases. In the following sample each reducer only gets its own part ("slice") of the state, which reduces its complexity.
Dec 19, 2020 · Just like Rostyslav said, you're not using useReducer in the right way. This is different from the useState hook: in that one, the parameter that it receives will serve as a default value for the defined variable within the component' state, which is why it's possible to leave it blank.
Dec 20, 2019 · The proper way to add types using typescript with useReducer HOOK. 1. useReducer type with optional ...
Dec 10, 2019 · Here's how useReducer is different from Redux: You can reuse the reducer itself, but if you have multiple useReducers, the state and dispatch returned from each one, as well as the initial state, will be separate instances.
