When comparing oldValues and newValues on React Hooks, the user has to rely on the useEffect. Of course, React is used to create a component with React hooks. It must be adaptive to state with components created by comparing oldValues and newValues forever. To know the steps professionally, you can hire react experts who handle React Hooks smoothly. 

Store Old Values in a Ref

Storing old values in a ref takes assigning values to re-rendering components. They ensure a good solution and persist in showing the render cycle forever. It has to write depending on the requirements by focusing on importing new values and old values in React Hooks. 

Example case:

import React, { useEffect, useRef, useState } from “react”;

const usePrevious = (value) => {

  const ref = useRef();

  useEffect(() => {

    ref.current = value;

  });

  return ref.current;

};

export default function App() {

  const [count, setCount] = useState(0);

  const prevCount = usePrevious(count);

  useEffect(() => {

    console.log(“prevCount: “, prevCount, “count: “, count);

  }, [prevCount, count]);

  return (

    <div className=”App”>

      <button onClick={() => setCount((c) => c + 1)}>increment</button>

      <p>{count}</p>

    </div>

  );

}

Create usePrevious Hook

Of course, the user has to rely on the previous state of the usePrevious command in React Hooks. It stands apart and thus showcases value parameters. The hook takes value in showing current property by ref to store value. The Hook takes value parameters by focusing on a state or prop value to store and compare. 

Ref to Store Value 

The user has to take useEffect with a callback option to set the current property to store value. They consider the 2nd argument for using the call back with value in a component and using it. 

Using the app, we can create a count state with a useState hook. It will adapt to storing previous values of count in the ref. It will add value and thus show a button to call with setCount to click and update count. The value of PrevCount uses the effect hook by passing an array with the 2nd argument. 

Here, you can find out how to call SetCount and click its update count to compare oldvalue and new values for React Hooks useEffect. 

And Then We Show the Count

By comparing old values and new values on React Hooks, it use the effects and thus compares patterns and justify a custom hook. It takes its own implementation details by focusing on const component=props. 

const Component = (props) => {

  const hasVal1Changed = useHasChanged(val1)

  useEffect(() => {

    if (hasVal1Changed ) {

      console.log(“val1 has changed”);

    }

  });

  return <div>…</div>;

};

const useHasChanged= (val: any) => {

    const prevVal = usePrevious(val)

    return prevVal !== val

}

const usePrevious = (value) => {

    const ref = useRef();

    useEffect(() => {

      ref.current = value;

    });

    return ref.current;

}

By taking a console log, it has to find out prevCount and assume the previous value of count. They ensure a good solution and find an accepted answer with alternative options. It does not require a custom hook by focusing on const component value. 

const Component = ({ receiveAmount, sendAmount }) => {

  const prevAmount = useRef({ receiveAmount, sendAmount }).current;

  useEffect(() => {

    if (prevAmount.receiveAmount !== receiveAmount) {

     // process here

    }

    if (prevAmount.sendAmount !== sendAmount) {

     // process here

    }

    return () => { 

      prevAmount.receiveAmount = receiveAmount;

      prevAmount.sendAmount = sendAmount;

    };

  }, [receiveAmount, sendAmount]);

};

Users have to assume reference to take previous values for process bits. They take a good one and conditional for beyond straight by comparison. It includes a simple solution and just to optimize the constant values in the receive amount and send values on the React Hooks by useEffect. 

const Component = ({ receiveAmount, sendAmount }) => {

  useEffect(() => {

     // process here

  }, [receiveAmount]);

  useEffect(() => {

     // process here

  }, [sendAmount]);

};

It is not a big thing to couple with a component. Old values and new values must be adaptive to functional components. They ensure a good solution and cannot be included in saving. For instance, it further updates the state update for possible implemented options. It would place well and make good use of userReducer. It is redux-like and thus capable of implementing the respective pattern. 

Of course, it has to rely on the use reducer and thus find explicit performance options. They ensure a good solution and include a call-back function that is extremely useful. They come with more options and can identify a use transition hook that uses an effective hook. It requires only a call back function and takes an array of dependencies.

Callback Function and an Array of Dependencies

• It uses the useEffect and takes component mounts
• There is no change and dependencies
• Hook the callback function to operate on dependencies change
• Dependencies should create performance transition based effects

const useTransition = (callback, deps) => {

  const func = useRef(null)

  useEffect(() => {

    func.current = callback

  }, [callback])

The user has to use the previous hook and add a value parameter with the previous value form. It must adapt to focusing on a high-end solution for creating a nonreactive property. So, it has to create a ref with a useref by creating a nonreactive property forever. It has to create useref by focusing on a high-end solution. 

And we return based on the re.current that has previous value. It must be applicable for us to change the call back option with ref.current and value on the non-reactive property. 

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Option 1 – Run useEffect When Value Changes

const Component = (props) => {

  useEffect(() => {

    console.log(“val1 has changed”);

  }, [val1]);

  return <div>…</div>;

};

Option 2 – useHasChanged Hook

By comparing its current value, we can compare old values to new values on react Hooks. By using useffect, it hides implementation details. 

const Component = (props) => {

const hasVal1Changed = useHasChanged(val1)

useEffect(() => {

    if (hasVal1Changed ) {

      console.log(“val1 has changed”);

    }

  });

Conclusion

Thus, this blog provides detailed information about comparing old and new values on reacting hooks. It shows possible things and can compare its values depending on the requirement. Using react Hooks, we can compare values by useEffect case in detail. 

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