How to push Multiple Objects into an array using useState hook

Question

I need to push the Multiple objects in to an array by using UseState hook, Here I am getting the multiple objects into "getallData", So I need to sent the all the multiple objects into setdataObject. But here I am not getting all the multiple objects data and getting an Empty Array..

 const [data, setData] = useState([])
  const [dataObject,setdataObject] = useState([{}])

 useEffect(()=>{
   fetch('http://localhost:3000/results')
   .then(res =>res.json())
   .then((results)=>{
    setData(results);
    //console.log(results);
    for(let i=0;i<results.length;i++){
      //console.log(results);
      const getallData={
        name :`${results[i].name.first} ${results[i].name.last}`,
        money : results[i].price.money.wealth
      }
      //console.log(getallData);
      setdataObject(getallData);
      console.log(dataObject);
    }
   })
 },[])

Mohammad Faisal · Accepted Answer · 2020-10-12 05:11:49Z

1

You are calling setdataObject inside a loop. Rather you can add the all datas into an array and set it at the end of the loop. Something like this

    const tempArray = []
    for(let i=0;i<results.length;i++){
      const getallData={
        name :`${results[i].name.first} ${results[i].name.last}`,
        money : results[i].price.money.wealth
      }
      tempArray.push(getallData)
    }
    setdataObject(tempArray);

Another thing. As setState functions are asynchronus so if you call console.log() immediately after changing any state value you will not get the changes immediately. As a result your following code is printing wrong output

 setdataObject(getallData);
 console.log(dataObject);    // WRONG !!!!

answered Oct 12, 2020 at 5:11

Mohammad Faisal

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2 Comments

Sundeep Over a year ago

Hi Mohammad your coding working fine, But how to check that setdataObject(temArray) , is getting all the data?? By using Debug, We can see all the data? because as you said Immediately after changing any state value I will not get the changes Immeditately

Mohammad Faisal Over a year ago

you can use useEffect hook to identify any change in the dataObject

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