Unable to update form field in react via prevState - reactjs

Question

I have a state variable as:
constructor(props) {
super(props)
this.state = {
fields: {
applicantName: '',
applicantType: '',
applicantAddress: '',
applicantContact: '',
buildingName: '',
buildingAddress: '',
area:'',
}
}
this.handleChange = this.handleChange.bind(this)
this.handleSubmit = this.handleSubmit.bind(this)
}
and I have a function :
handleChange(event) {
this.setState((prevState) => {
fields: {
...prevState.fields, //Unexpected token ..
{
event.target.name: event.target.value,
},
}
});
}
How I am not able to see any type of syntax here...but my module build fails and it says syntax error near '...'

Answer 1

you need return Object
handleChange(event) {
// note here => ({
this.setState((prevSate) => ({
fields: {
...prevState.fields,
//and there ..
[event.target.name]: event.target.value
})
});
}
UPDATE
Based on Abdullah suggestion, its better when you use ...prevState for wohle state:
handleChange(event) {
// note here => ({
this.setState((prevSate) => ({
// note change here
...prevState,
fields: {
...prevState.fields,
//and there ..
[event.target.name]: event.target.value
})
});
}
UPDATE 2
based on PraveenRaoChavan comment:
typo fix:
need use event not e

Answer 2

handleChange(event) {
this.setState(prevState => ({
fields: {
...prevState.fields,
{
event.target.name: e.target.value,
},
}
}));
}

Answer 3

You have a typo in there
change
this.setState((prevSate) => { }
to
this.setState((prevState) => { }