在数组中添加多个值

Question

In my application, in React i have next situation: I have input where i add different values when i click on save . The value from input is converted from string to array. So, first time i added a text, i clicked save, and i have 1 value in array. Second time, i add another text, i click, on save and the first value is changed by second. I store value in this state:

 const [value, setValue] = useState([here comes my value]);

I want to concat the value one after one and i did:

 useEffect(()=> { setAllValues([...value, value]) }, [value])

..but this does't work. How to store all values in one array?

Answer 1

Use the functional form of setState :

 setAllValues(prevValue => [...prevValue, newValue])

Answer 2

To perform that operation you would need two states

// one state for array
const [valueArray, setValueArray] = useState([here comes my value]);

// and another state for string
const [value, setValue] = useState('');


// then onSave function
const onSave = () => {
  setValueArray([  ...valueArray, value ]);
  setValue('');
}