React update existing object in array of objects

Question

I have 1 input:

 <input
     type="text"
     name={item.job_n}
     defaultValue={item.azienda}
     readOnly={isReadonly}
     onChange={handleChange}

And onChange I'm adding the inputs value and name as an Object to an array of Objects in useState=([]), therefore my array looks like this: [{azienda:'', job_n:''}, {azienda:'', job_n:''}]

const [azienda, setAzienda] = useState([]);
    const handleChange =(e)=>{
        {
            const azienda_name = e.target.value
            const job_n = e.target.name            
            setAzienda((prevState) => [...prevState, {azienda: azienda_name, job_n: job_n}])                                    
        }   
    }

The code works fine and a new Object is added to my array each time an onchange event occurs. The issue I'm having is that if an object with job_n already exists in the array I'd need to update that object and not create a new object for each onchange.

Scar · Accepted Answer · 2022-07-15 22:13:01Z

2

I have changed the variables from italian to english so that everyone can understand them, and also changed some variables to follow the javascript naming conventions.

function handleChange(e) {
    const businessName = e.target.value;
    const jobName = e.target.name;
    const jobIndex = business.findIndex(v => {
        return v["jobName"] === jobName;
    });
    if (jobIndex === -1) {
        setBusiness([...business, { businessName, jobName }]);
        return;
    }
    const businessClone = [...business];
    businessClone[jobIndex] = { businessName, jobName };
    setBusiness(businessClone);
}

answered Jul 15, 2022 at 22:13

Scar

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2 Comments

zacaaron Over a year ago

This seems to work, grazie!

Scar Over a year ago

@zacaaron np, flag it as the answer.

user13937286 · Accepted Answer · 2022-07-15 21:58:56Z

0

Change your code to,

setAzienda((prevState) => {
      const jobExistIndex = prevState.findIndex(obj => obj.job_n === job_n)
      const jobExist = prevState[jobExistIndex]
      if (jobExist) {
          const newState = [...prevState]
          newState[jobExistIndex] = {...jobExist, job_n: job_n}
          return newState 
      }
      else {
          const newState = [...prevState]
          return [...newState, {azienda: azienda_name, job_n: job_n}]
      }

answered Jul 15, 2022 at 21:58

user13937286

1 Comment

Codebling Over a year ago

Still doesn't work. Need to change azienda in found value, not job_n

Okan Karadag · Accepted Answer · 2022-07-15 23:27:30Z

0

const handleChange = e =>{
{
    const azienda_name = e.target.value;
    const job_n = e.target.name;
    const existIndex = azienda.findIndex(p => p.job_n === job_n);
    if(existIndex != -1)
    {
       azienda[existIndex].azienda_name = azienda_name 
    }
    else
    {
       azienda.push({azienda_name : azienda_name, job_n: job_n})
    }        
    setAzienda(azienda);
}

edited Jul 15, 2022 at 23:27

answered Jul 15, 2022 at 22:15

Okan Karadag

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10 Comments

Scar Over a year ago

that would be invalid, as you are editing a const variable.

Okan Karadag Over a year ago

@Scar the variable is object, if it is a primitive type, throw errors.

Scar Over a year ago

I don't get what you mean but const [azienda, setAzienda] = useState([]); defines azienda as a constant, and therefore if u try to change it like u did after you first if condition it will throw.

Okan Karadag Over a year ago

Could you looking developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…

Scar Over a year ago

@Codebling I don't know, but i've tried it in runtime and it gives out error.

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