reading-notes

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Advanced State with Reducers

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Review, Research, and Discussion

How can we ensure that an effect hook runs only once ❓ 📁

If we pass an empty array [] , it just renders the component only once like componentDidMount.

Can useState() update more than one state variable at the same time ❓ 📁

Unlike the setState in class components, the setState returned from useState doesn’t merge objects with existing state, it replaces the object entirely.

Is useState() synchronous ❓ 📁

useState and setState both are asynchronous. They do not update the state immediately but have queues that are used to update the state object.

useReducer

• const [state, dispatch] = useReducer(reducer, initialArg, init);

• 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.

Ultimate Guide to useReducer

• useReducer helps you manage complex state logic in React applications. When combined with other Hooks like useContext, useReducer can be a good alternative to Redux or MobX — indeed, it can sometimes be an outright better option.

How does useReducer work?

• useReducer returns an array that holds the current state value and a dispatch function, to which you can pass an action and later invoke.

📁 useReducer hook
📁 Ultimate Guide to useReducer