The reason is, in state you defined:
this.state = { fields: {} }
fields as a blank object, so during the first rendering this.state.fields.name
will be undefined
, and the input field will get its value as:
value={undefined}
Because of that, the input field will become uncontrolled.
Once you enter any value in input, fields
in state gets changed to:
this.state = { fields: {name: 'xyz'} }
And at that time the input field gets converted into a controlled component; that’s why you are getting the error:
A component is changing an uncontrolled input of type text to be
controlled.
Possible Solutions:
1- Define the fields
in state as:
this.state = { fields: {name: ''} }
2- Or define the value property by using Short-circuit evaluation like this:
value={this.state.fields.name || ''} // (undefined || '') = ''