react native setstate usestate nested object code example

Example 1: access nested state value in hookstate

// However, there is a nested state method, which allows to access nested state by name.

// example :- 
state = {
  user: {
    name: { firstName: 'Kaushal', lastName: 'Shah' }
  }
};

// To access state => 
state

// To access user => 
state.user or state.nested('user')

// To access name => 
state.user.nested('name')

// To access firstName => 
state.user.nested('name').nested('firstName')

Example 2: usestate nested object

const [currentApp, setCurrentApp] = useState({
        userID: null,
        hospitalName: null, 
        hospitalID: null,
        date: null,
        time: null,
        timestamp: null,
        slots: 1,
        appointmentType: null
    })
    
const [appointmentType, setAppointmentType] =  useState({
        Granulocytes: {
            bloodType:null,
            message: null
        }
})

const handleGranChange = (e) => {
        setAppointmentType({...appointmentType, Granulocytes : {
            ...appointmentType.Granulocytes, 
            [e.target.id] : e.target.value}
        })
		setCurrentApp({ ...currentApp, ['appointmentType'] : appointmentType  })
        console.log(currentApp)
}