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August 29, 2022 05:55 am GMT

How to Solve Changes Not Reflecting When useState Set Method Applied?

Do you know that React.js is the most preferred web framework, used by 40.14% of developers in 2021? While it is widely used by developers globally, certain errors are observed by the developers. The useState set method error is one such issue related to the state management in React.js. Hence, you can hire react developers who have the expertise in handling these errors is recommended. Let us go through this error and the top solutions for the same.

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React hooks A quick flashback:

The different React components have a built-in state object which is the encapsulated data to store the assets between the different component renderings. This state is the JavaScript data structure. The users interaction with this state can change the user-interface looks, which is now represented by a new state than the previous state.

With the increase in the application data, React engineers need to use the different React hooks and Redux for dedicated state management. React hooks are the specific functions which hook the React features and states from different functional components. Hence, React hooks are widely used to use React features without writing a class. Let us now move to the useState hooks and issues related to the useState set method.

What is useState in React?

Developers looking to incorporate the state variables in functional components use the useState hook in the program. The initial state is passed to the function and returns a variable with the current state value along with another function to update this value. Hence, useState is called inside the function to create a single piece of state associated with the component.

The state can be any type with hooks, even if the state in a class is always an object. Every state piece holds a single value like an array, a Boolean, or another type. The useState is widely used in the local component state. This hook can be used with other key state management solutions for large projects.

The useState can be declared in React as:

  • React.useState
  • import React , { useState } from react ;

It allows the declaration of the one state variable, which can be of any type at any specific time. A simple example of the same is:

import React, { useState } from react;const Message = () => {const messageState = useState();const listState = useState([]);}

This method takes the initial value of the state variable. Let us look at the error in the useState set method.

What is the useState set method not reflecting a change immediately error?

The useState hook is one of the in-built hooks in React and is backwards compatible. While the React developers can create custom hooks, some other popular ones are seducer, effect, etc.

The useState hook adds React state to other functional components. The following example shows the State Variable declaration in the class and the count state initialization with 0 by setting this. state to {count : 0}.

class Example extends React.Component {constructor(props) {super(props);this.state = {count: 0};

In this, it is not possible to read this.state and hence useState hook can be directly used as:

function Example() {const [ count, setCount ] = useState(0);}

Let us now have a quick look at the error where the useState set method is not reflecting the change. The following code is taken under consideration:

const [posts, setPosts] = useState([]);useEffect(() => {const myData = await axios({method: "post",url: "my_api_call",});setPosts(myData.data);}, []);

Before jumping to the different solutions for the issue related to the useState method, it is important to know the reason. When the useState set method is not reflecting a change immediately, it may be due to the current closure of the state variable. Hence, it is still referring to the old value of the state. It is the failure of the re-render to reflect the updated value of the state.

The useState set method is asynchronous; hence, the updates are not reflected immediately. However, this is not the reason for the change not getting reflected immediately in the method. Hence, all you need to do is to go for any of the methods which reflect the changes in the useState set method immediately.

Methods to solve the error when the useState set method is not reflecting an immediate change:

Some of the quick methods to solve the situation when the useState set method is not reflecting a change immediately include:

Using the useEffect hook:

The easiest solution for solving this issue with the useState set method is to use the useEffect hook. It is the popular hook used to accomplish side effects in the program components. The main side effects performed by the useEffect hook are timers, directly updating the DOM, data fetching, etc. The following code can be used to update the posts.

useEffect(() => {// setPosts Here}, [posts]);

Using a Temp Variable: In case the useState method is not reflecting the immediate change, any temporary variable can be used. The use of a temporary variable with await may ask the API to take time and then set the value. The example for using the temporary variable is:

const [posts, setPosts] = useState([]);useEffect(() => {const myData = await axios({method: "post",url: "my_api_call",});const newPosts = await myData.data;setPosts(newPosts);}, []);

Merging response:

Another solution for the useState set method which is not reflecting the change immediately is to merge the responses. The callback is the function passed as an argument to the other function. Hence, any function can call the other function using callback. It is achieved by using the callback syntax of the state updation with the precise use of the spread syntax. The example for the same is:

setPosts(prevPostsData=> ([...prevPostsData, ...newPostsData]));

Try using React.useRef():

The useref hook is used to persist values between the renders. It is used to access a DOM element directly or to store a mutable value which doesnt cause a re-render when updated. Hence, useRef hook is used to calculate the number of times an application renders in the useState hook.

The simple method to use React.useRef() for observing an instant change in the React hook is:

const posts = React.useRef(null);useEffect(() => {posts.current='values';console.log(posts.current)}, [])

Wrapping Up:

Hence, it is easy to get over this useState set method error quickly after understanding all about the useState in React. The four different solutions to solve the useState set method include using the useEffect hook, temporary variable, merging responses, and using the React.useRef(). All you need to do is try these methods to find the ideal solution to this error in React.js


Original Link: https://dev.to/kuldeeptarapara/how-to-solve-changes-not-reflecting-when-usestate-set-method-applied-ic4

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