Is there a generic way to set state in React Hooks? How to manage multiple states?

Question

I have a question, if I can use useState generic in React Hooks, just like I can do this in React Components while managing multiple states?

state = {
  input1: "",
  input2: "",
  input3: ""
  // .. more states
};

handleChange = (event) => {
  const { name, value } = event.target;
  this.setState({
    [name]: value,
  });
};

Answer 1

Yes, with hooks you can manage complex state (without 3rd party library) in three ways, where the main reasoning is managing state ids and their corresponding elements.

1. Manage a single object with multiple states (notice that an array is an object).
2. Use useReducer if (1) is too complex.
3. Use multiple useState for every key-value pair (consider the readability and maintenance of it).

Check out this:

// Ids-values pairs.
const complexStateInitial = {
  input1: "",
  input2: "",
  input3: ""
  // .. more states
};

function reducer(state, action) {
  return { ...state, [action.type]: action.value };
}

export default function App() {
  const [fromUseState, setState] = useState(complexStateInitial);

  // handle generic state from useState
  const onChangeUseState = (e) => {
    const { name, value } = e.target;
    setState((prevState) => ({ ...prevState, [name]: value }));
  };

  const [fromReducer, dispatch] = useReducer(reducer, complexStateInitial);

  // handle generic state from useReducer
  const onChangeUseReducer = (e) => {
    const { name, value } = e.target;
    dispatch({ type: name, value });
  };
 
  return (
    <>
      <h3>useState</h3>
      <div>
        {Object.entries(fromUseState).map(([key, value]) => (
          <input
            key={key}
            name={key}
            value={value}
            onChange={onChangeUseState}
          />
        ))}
        <pre>{JSON.stringify(fromUseState, null, 2)}</pre>
      </div>

      <h3>useReducer</h3>
      <div>
        {Object.entries(fromReducer).map(([key, value]) => (
          <input
            name={key}
            key={key}
            value={value}
            onChange={onChangeUseReducer}
          />
        ))}
        <pre>{JSON.stringify(fromReducer, null, 2)}</pre>
      </div>
    </>
  );
}

Notes

• Unlike the setState method found in class components, useState does not automatically merge update objects. You can replicate this behavior by combining the function updater form with object spread syntax:

setState(prevState => {
  // Object.assign would also work
  return {...prevState, ...updatedValues};
});

Refer to React Docs.