我用reduce搜索做嵌套更新:

例子:

状态中的嵌套变量:

state = {
    coords: {
        x: 0,
        y: 0,
        z: 0
    }
}

功能:

handleChange = nestedAttr => event => {
  const { target: { value } } = event;
  const attrs = nestedAttr.split('.');

  let stateVar = this.state[attrs[0]];
  if(attrs.length>1)
    attrs.reduce((a,b,index,arr)=>{
      if(index==arr.length-1)
        a[b] = value;
      else if(a[b]!=null)
        return a[b]
      else
        return a;
    },stateVar);
  else
    stateVar = value;

  this.setState({[attrs[0]]: stateVar})
}

Use:

<input
value={this.state.coords.x}
onChange={this.handleTextChange('coords.x')}
/>

创建一个状态的副本:

let someProperty = JSON.parse(JSON.stringify(this.state.someProperty))

对该对象进行更改:

someProperty.flag = "false"

现在更新状态

this.setState({someProperty})

如果你想动态设置状态

下面的示例动态设置表单的状态，其中状态中的每个键都是object

 onChange(e:React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement>) {
    this.setState({ [e.target.name]: { ...this.state[e.target.name], value: e.target.value } });
  }

虽然你问的是基于类的React组件的状态，但useState钩子也存在同样的问题。更糟糕的是:useState钩子不接受部分更新。所以当useState钩子被引入时，这个问题就变得非常相关了。

我决定发布以下答案，以确保这个问题涵盖了使用useState钩子的更现代的场景:

如果你有:

const [state, setState] = useState({
  someProperty: {
    flag: true,
    otherNestedProp: 1
  },
  otherProp: 2
})

你可以通过克隆当前数据并修补所需的数据段来设置嵌套属性，例如:

setState(current => { ...current,
  someProperty: { ...current.someProperty,
    flag: false
  }
});

或者您可以使用Immer库来简化对象的克隆和修补。

或者你可以使用Hookstate库(免责声明:我是一名作家)来简单地管理复杂的(本地和全局)状态数据，并提高性能(阅读:不用担心渲染优化):

import { useHookstate } from '@hookstate/core'

const state = useHookstate({
  someProperty: {
    flag: true,
    otherNestedProp: 1
  },
  otherProp: 2
})

获取要渲染的字段:

state.someProperty.flag.get()
// or 
state.get().someProperty.flag

设置嵌套字段:

state.someProperty.flag.set(false)

下面是Hookstate示例，其中的状态被深度递归嵌套在树状数据结构中。

试试下面的代码:

this.setState({ someProperty: {flag: false} });

这样就足够了，

const isObject = (thing) => {
    if(thing && 
        typeof thing === 'object' &&
        typeof thing !== null
        && !(Array.isArray(thing))
    ){
        return true;
    }
    return false;
}

/*
  Call with an array containing the path to the property you want to access
  And the current component/redux state.

  For example if we want to update `hello` within the following obj
  const obj = {
     somePrimitive:false,
     someNestedObj:{
        hello:1
     }
  }

  we would do :
  //clone the object
  const cloned = clone(['someNestedObj','hello'],obj)
  //Set the new value
  cloned.someNestedObj.hello = 5;

*/
const clone = (arr, state) => {
    let clonedObj = {...state}
    const originalObj = clonedObj;
    arr.forEach(property => {
        if(!(property in clonedObj)){
            throw new Error('State missing property')
        }

        if(isObject(clonedObj[property])){
            clonedObj[property] = {...originalObj[property]};
            clonedObj = clonedObj[property];
        }
    })
    return originalObj;
}

const nestedObj = {
    someProperty:true,
    someNestedObj:{
        someOtherProperty:true
    }
}

const clonedObj = clone(['someProperty'], nestedObj);
console.log(clonedObj === nestedObj) //returns false
console.log(clonedObj.someProperty === nestedObj.someProperty) //returns true
console.log(clonedObj.someNestedObj === nestedObj.someNestedObj) //returns true

console.log()
const clonedObj2 = clone(['someProperty','someNestedObj','someOtherProperty'], nestedObj);
console.log(clonedObj2 === nestedObj) // returns false
console.log(clonedObj2.someNestedObj === nestedObj.someNestedObj) //returns false
//returns true (doesn't attempt to clone because its primitive type)
console.log(clonedObj2.someNestedObj.someOtherProperty === nestedObj.someNestedObj.someOtherProperty)