React将useState()与Object挂钩

在嵌套对象中，在React with Hooks中更新状态的正确方法是什么?

export Example = () => {
  const [exampleState, setExampleState] = useState(
  {masterField: {
        fieldOne: "a",
        fieldTwo: {
           fieldTwoOne: "b"
           fieldTwoTwo: "c"
           }
        }
   })

如何使用setExampleState将exampleState更新为a(附加字段)?

const a = {
masterField: {
        fieldOne: "a",
        fieldTwo: {
           fieldTwoOne: "b",
           fieldTwoTwo: "c"
           }
        },
  masterField2: {
        fieldOne: "c",
        fieldTwo: {
           fieldTwoOne: "d",
           fieldTwoTwo: "e"
           }
        },
   }
}

b(改变值)?

const b = {masterField: {
        fieldOne: "e",
        fieldTwo: {
           fieldTwoOne: "f"
           fieldTwoTwo: "g"
           }
        }
   })

当前回答

你想要创建状态的对象

let teams = {
  team: [
    {
      name: "one",
      id: "1"
    },
  ]
}

使团队的状态为对象

const [state, setState] = useState(teams);

像这样更新状态

setState((prevState)=>({...prevState,team:[
     ...prevState.team,
     {
     name: "two",
      id: "2"
     }
]}))

更新后状态变为

{
  team: [
    {
      name: "one",
      id: "1"
    },
    {
      name: "two",
      id: "2"
    }
  ]
}

要渲染项目根据当前状态使用地图功能

{state.team.map((curr_team) => {
      return (
        <div>
           <p>{curr_team.id}</p>
           <p>{curr_team.name}</p>
        </div>
      )
})}

2021-11-26 15:52:55

其他回答

你想要创建状态的对象

let teams = {
  team: [
    {
      name: "one",
      id: "1"
    },
  ]
}

使团队的状态为对象

const [state, setState] = useState(teams);

像这样更新状态

setState((prevState)=>({...prevState,team:[
     ...prevState.team,
     {
     name: "two",
      id: "2"
     }
]}))

更新后状态变为

{
  team: [
    {
      name: "one",
      id: "1"
    },
    {
      name: "two",
      id: "2"
    }
  ]
}

要渲染项目根据当前状态使用地图功能

{state.team.map((curr_team) => {
      return (
        <div>
           <p>{curr_team.id}</p>
           <p>{curr_team.name}</p>
        </div>
      )
})}

2021-11-26 15:52:55

如果你使用布尔值和数组，这可以帮助你:

const [checkedOrders, setCheckedOrders] = useState<Record<string, TEntity>>({});

const handleToggleCheck = (entity: TEntity) => {
  const _checkedOrders = { ...checkedOrders };
  const isChecked = entity.id in checkedOrders;

  if (isChecked) {
    delete _checkedOrders[entity.id];
  } else {
    _checkedOrders[entity.id] = entity;
  }

  setCheckedOrders(_checkedOrders);
};

2022-05-24 19:51:50

答案已经有了，但是这种类型没有被提到，所以看看这种类型的例子…

 const[data,setdata]= useState({
    username: [
      email,
      "required", 
      //...some additional codes
    ],
    password: [
      password,
      "required|password-5",
     //..additional code if any..
    ],
  })

**要在输入字段中更新状态变量email，您可以添加类似的代码与您的变量名**

          <Input
              onChangeText={(t) => setdata(prevState=>({...prevState,username:{[0]:t}}))}
              value={data.username[0]}
            />

2022-09-15 08:58:03

我迟到了。：）

@aseferov回答在意图是重新进入整个对象结构时非常有效。然而，如果目标/目标是更新Object中的特定字段值，我认为下面的方法更好。

情境:

const [infoData, setInfoData] = useState({
    major: {
      name: "John Doe",
      age: "24",
      sex: "M",
    },

    minor:{
      id: 4,
      collegeRegion: "south",

    }

  });

更新特定的记录需要回调到之前的状态prevState

在这里:

setInfoData((prevState) => ({
      ...prevState,
      major: {
        ...prevState.major,
        name: "Tan Long",
      }
    }));

也许

setInfoData((prevState) => ({
      ...prevState,
      major: {
        ...prevState.major,
        name: "Tan Long",
      },
      minor: {
        ...prevState.minor,
        collegeRegion: "northEast"

    }));

我希望这对试图解决类似问题的人有所帮助。

2020-04-13 16:48:35

谢谢Philip，这帮助了我-我的用例是我有一个有很多输入字段的表单，所以我保持初始状态为对象，我不能更新对象状态。上面的帖子帮助了我:)

const [projectGroupDetails, setProjectGroupDetails] = useState({
    "projectGroupId": "",
    "projectGroup": "DDD",
    "project-id": "",
    "appd-ui": "",
    "appd-node": ""    
});

const inputGroupChangeHandler = (event) => {
    setProjectGroupDetails((prevState) => ({
       ...prevState,
       [event.target.id]: event.target.value
    }));
}

<Input 
    id="projectGroupId" 
    labelText="Project Group Id" 
    value={projectGroupDetails.projectGroupId} 
    onChange={inputGroupChangeHandler} 
/>

2020-05-13 14:24:06

React将useState()与Object挂钩

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