Cannot set Object value to passed value: InventoryItem.js:7 Uncaught TypeError: Cannot set properties of undefined (setting ‘itemName’)

I am trying to pass the value from 3 TextInput’s to a constructor on a button press. The values themselves are passing fine, I can verify that when I console.log() them. But the object property itself is having a type error thrown while I’m trying to set it’s value, which doesn’t make much sense to me. I’m inexperienced with JavaScript, but I’ve never seen a type error on something I’m trying to set the value of.

“Uncaught TypeError: Cannot set properties of undefined (setting ‘itemName’) at InventoryItem (InventoryItem.js:7:1)”

Taking the text Input:

const AddItem = props => {

  const [itemName, setName] = useState('');
  const [ExpirationDate, setExp] = useState('');
  const [ReminderDate, setRem] = useState('');

    return(
    <View style={styles.header}>
      <TextInput
        style = {styles.input}
        placeholder = "Enter Item Name"
        onChangeText={(val) => setName(val)}/>

      <TextInput
        style = {styles.input}
        placeholder = "Enter Expiration Date (mm/dd/yyyy)"
        onChangeText={(val) => setExp(val)}/>

      <TextInput
        style = {styles.input}
        placeholder = "Enter Reminder Date (mm/dd/yyyy)"
        onChangeText={(val) => setRem(val)}/>

      <Text>Name: {itemName}, Expiration: {ExpirationDate}, Reminder: {ReminderDate}</Text>

      <TouchableOpacity style={styles.btn} onPress={() => InventoryItem(itemName, ExpirationDate, ReminderDate)}>
        <Text style={styles.btnText}> <Icon name="plus" size={20}/>Add Item</Text>
      </TouchableOpacity>

      <TouchableOpacity style={styles.btn} onPress={() => props.navigation.navigate('Home')}>
        <Text style={styles.btnText}>Return Home</Text>
      </TouchableOpacity>
    </View>
  )
}

Constructor:

export function InventoryItem(name, ExpirationDate, ReminderDate) {
    console.log("Here");
    console.log(name)
    console.log(ExpirationDate)
    console.log(ReminderDate)

    this.itemName = name;
    this.ExpirationDate = ExpirationDate;
    this.ReminderDate = ReminderDate;

    console.log(this.itemName);
    console.log(this.ExpirationDate);
    console.log(this.ReminderDate);
}

Console Log

I was initially casting the parameters themselves to strings, and trying other things like that before this.itemName = name and such, then I realized it wasn’t the passed values that are the problem, but “this.itemName = ” itself thats having the type error. And I’m not sure what to do with that.