如果有人正在搜索useState()钩子，则更新为对象

- Through Input

        const [state, setState] = useState({ fName: "", lName: "" });
        const handleChange = e => {
            const { name, value } = e.target;
            setState(prevState => ({
                ...prevState,
                [name]: value
            }));
        };

        <input
            value={state.fName}
            type="text"
            onChange={handleChange}
            name="fName"
        />
        <input
            value={state.lName}
            type="text"
            onChange={handleChange}
            name="lName"
        />
   ***************************

 - Through onSubmit or button click
    
        setState(prevState => ({
            ...prevState,
            fName: 'your updated value here'
         }));

可以使用useReducer钩子来管理复杂的状态，而不是useState。要做到这一点，首先初始化状态和更新函数如下所示:

const initialState = { name: "Bob", occupation: "builder" };
const [state, updateState] = useReducer(
  (state, updates) => ({ ...state, ...updates }),
  initialState
);

然后你可以通过只传递部分更新来更新状态，就像这样:

updateState({ occupation: "postman" })

我已经给出了两个追加，整个对象更新，具体的关键更新的解决方案的例子

追加和修改都可以通过一个简单的步骤来完成。我认为这是更稳定和安全的，没有不可变或可变的依赖。

这就是追加新对象的方法

setExampleState(prevState => ({
    ...prevState,
    masterField2: {
        fieldOne: "c",
        fieldTwo: {
            fieldTwoOne: "d",
            fieldTwoTwo: "e"
        }
    },
}))

假设您想再次修改masterField2对象。可能有两种情况。您想要更新整个对象或更新对象的特定键。

更新整个对象-这里masterField2键的整个值将被更新。

setExampleState(prevState => ({
    ...prevState,
    masterField2: {
        fieldOne: "c",
        fieldTwo: {
            fieldTwoOne: "d",
            fieldTwoTwo: "e"
        }
    },
}))

但是如果你只想改变masterField2对象中的fieldTwoOne键呢?你可以这样做。

let oldMasterField2 = exampleState.masterField2
oldMasterField2.fieldTwo.fieldTwoOne = 'changed';
setExampleState(prevState => ({
    ...prevState,
    masterField2: oldMasterField2
}))

，就像这个例子:

首先创建对象的状态:

const [isSelected, setSelection] = useState([{ id_1: false }, { id_2: false }, { id_3: false }]);

然后更改它们的值:

// if the id_1 is false make it true or return it false.

onValueChange={() => isSelected.id_1 == false ? setSelection([{ ...isSelected, id_1: true }]) : setSelection([{ ...isSelected, id_1: false }])}

我认为更优雅的解决方案是创建更新后的状态对象，同时保留以前的state值。需要更新的Object属性可以以这样的数组形式提供

import React,{useState, useEffect} from 'react'
export default function Home2(props) {
    const [x, setX] = useState({name : '',add : {full : '', pin : '', d : { v : '' }}})
    const handleClick = (e, type)=>{
        let obj = {}
        if(type.length > 1){
            var z = {}
            var z2 = x[type[0]]
        
        type.forEach((val, idx)=>{
            if(idx === type.length - 1){
                z[val] = e.target.value
            }
            else if(idx > 0){
                Object.assign(z , z2) /*{...z2 , [val]:{} }*/
                z[val] = {}
                z = z[val]
                z2 = z2[val]
            }else{
                z = {...z2}
                obj = z
            }
        })
    }else obj = e.target.value
    setX( { ...x ,   [type[0]] : obj  } )
    
}
return (
    <div>
        <input value = {x.name} onChange={e=>handleClick(e,["name"])}/>
        <input value = {x.add.full} onChange={e=>handleClick(e,["add","full"])}  />
        <input value = {x.add.pin} onChange={e=>handleClick(e,["add","pin"])}  /><br/>
        <input value = {x.add.d.v} onChange={e=>handleClick(e,["add","d","v"])}  /><br/>
        {x.name} <br/>
        {x.add.full} <br/>
        {x.add.pin} <br/>
        {x.add.d.v}
    </div>
)
}

最初我在useState中使用object，但后来我移动到useReducer钩子用于复杂的情况。重构代码时，我感到性能有所提高。

当您有涉及多个子值的复杂状态逻辑时，或者当下一个状态依赖于前一个状态时，useReducer通常比useState更可取。

useReducer React文档

我已经实现了这样的钩子供我自己使用:

/**
 * Same as useObjectState but uses useReducer instead of useState
 *  (better performance for complex cases)
 * @param {*} PropsWithDefaultValues object with all needed props 
 * and their initial value
 * @returns [state, setProp] state - the state object, setProp - dispatch 
 * changes one (given prop name & prop value) or multiple props (given an 
 * object { prop: value, ...}) in object state
 */
export function useObjectReducer(PropsWithDefaultValues) {
  const [state, dispatch] = useReducer(reducer, PropsWithDefaultValues);

  //newFieldsVal={[field_name]: [field_value], ...}
  function reducer(state, newFieldsVal) {
    return { ...state, ...newFieldsVal };
  }

  return [
    state,
    (newFieldsVal, newVal) => {
      if (typeof newVal !== "undefined") {
        const tmp = {};
        tmp[newFieldsVal] = newVal;
        dispatch(tmp);
      } else {
        dispatch(newFieldsVal);
      }
    },
  ];
}

更多相关的钩子。