Reactjs - React: State in State?

JGreen
June 21, 2023
214 views
0 votes
2 Answers

I’m new in react.
What should i do to display a state in dynamic context?

In the example, when props.something changes, set displayed text state1 depending on the props.something value.
If props.something is NOT 1, put a checkbox named checkbox1 in state1 and show the checked state.

Actually in this case, checked state doesn’t change even if the checkbox1 was clicked.

Any ideas?

const Child = (props) => {
   const [checked, setChecked] = useState(false);
   const [state1, setState1] = useState(<></>);
   useEffect(() => {
       if(props.something === 1){
           setState1(<div>something is 1!</div>);
       }
       else{
           setState1(<div>
                <input type="checkbox" name="checkbox1" onChange={() => 
                   setChecked((prevState) => return !prevState;)
                 } defaultChecked={false} />
                State is {checked ? "TRUE" : "FALSE"}
            </div>);
       }
   }, [props.something]);

   return (<>{state1}</>);
}

EDIT:

Thanks to give some suggestions!

In actual project, the Child component is used to show data-fetching state — Parent component fetches some data from the online database. Parent component sends "props.something === 1" to the Child if the app starts to fetch data, and sends except 1 when the task was done.
I use checkbox1 to delete the item got from the database.

Tags: react-hooks reactjs

Answers

I think you don’t have the right approuch to this situation, you can conditionaly render things with the states, is not needed that you use a state to keep your html I did a bit of refactor on your code

import React, { useState, useEffect } from 'react';

export function App() { // app is the main component
  const ChildrenComponent = ({something}) => { // destructuring Props
    
  const [checked, setChecked] = useState(false);
  const [state1, setState1] = useState(0); // just a normal state

  useEffect(() => {
    setState1(something); // set the state when the props change
  }, [something]);

  return (
    <>
      {state1 === 1 ? ( 
        <div>something is 1!</div>
      ) : ( 
        <div>
          <input
            type='checkbox'
            name='checkbox1'
            onChange={() => setChecked(!checked)}
            defaultChecked={false}
          />
          State is {checked ? 'TRUE' : 'FALSE'}
        </div>
      )}
    </>
  );
}
  

  return <>
  <ChildrenComponent something={1}/> // test1
  <ChildrenComponent something={2}/> // test2
  </>
}

on this script we have a childrenComponent that can be imported or defined in the same file, that component get a ‘something’ prop and set a set based in that. Then render conditionaly the text or the checkbox usin a ternary operator.)

You can just check props to understand what you need to render.

export function App({ something }) {
    
  const [checked, setChecked] = useState(false);

  if(something === 1){
    return  <div>something is 1!</div>;
  }

  return (
    <div>
      <input
        type='checkbox'
        name='checkbox1'
        onChange={() => setChecked(!checked)}
        defaultChecked={false}
      />
      State is {checked ? 'TRUE' : 'FALSE'}
    </div>
  )
}

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Reactjs – React: State in State?

Answers