Undefined is not an object [React Native]

February 21, 2022

I’m with little issues with text inputs.

I have a screen with 3 text inputs, each have his own state. The problem occurs when I try to capture the value enter from the user and save it in a state, but i have "undefined is not an object in the setState". I read various threads, and I tried those solves, but I still keeping that problem.

Here I detach how I thought.

//Here I declare the state "Nombre" from a props sending by another screen

const [stateNombre, setStateNombre] = useState(JSON.stringify(param_nombre));

//Here I declare the TextInput

<TextInput
        id="text_nombre"
        placeholder={"Nombre"}
        style={styles.data_input}
        autoCorrect={false}
        blurOnSubmit
        placeholderTextColor="#777"
        autoCapitalized="words"
        multiline={true}
        onChangeText={text => this.setStateNombre(text.target.value)}
      ></TextInput>

//Here a picture of the problem

>Solution :

It seems you are combined both Class Components and Functional components Together
Why I am Saying your Using useState from Functional components and this.setStateNombre from Class Components + Functional components.Its some kind of weird code.

when it comes to your Problem First log(JSON.stringify(param_nombre))

and For TextInput [components and uncontrolled components]

<TextInput
        value={stateNombre}
        id="text_nombre"           
        placeholder={"Nombre"}
        style={styles.data_input}
        autoCorrect={false}
        blurOnSubmit
        placeholderTextColor="#777"
        autoCapitalized="words"
        multiline={true}
        onChangeText={(e) => setStateNombre(e.target.value)}
      />