Set array items in react js state

Question

Here I have a state which its initial value is an empty obj.

const [error, setError] = useState({});

In the next step, I'm checking if there is vacant input, set its key to the error state :

if (emptyInputs.length) {
            emptyInputs.forEach(key => setError({ ...error, [key]: true }));

but only one of the empty inputs name sets to my error state:

is there anyone face to this problem?

First don't provide the code snippet as image, instead provide them as real code snippet. Next provide the data that you receive from emptyInputs .. — Maniraj Murugan
– Maniraj Murugan, Commented Nov 22, 2021 at 6:33

MOHD SHAHZAIB · Accepted Answer · 2021-11-22 06:45:33Z

1

When you are looping through the emptyInput for each item you are assigning a new object to the error state because of that you are losing the previous state/key, first of all, you will have to copy the previous object to keep its values and then assign a new key like so.

This is a recommended way to set the state if your state depends on the previous state.

emptyInputs.forEach(key => setError(prevState => ({...prevState, [key]: true})))

This is not a recommended way to update the state like this because this way doesn't guarantee getting the latest state for each update if your state changes very frequently.

emptyInputs.forEach(key => setError({...error, [key]: true}))

answered Nov 22, 2021 at 6:45

MOHD SHAHZAIB

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