How can I make a picker in react native required - react-native

Question

I have created a signup form in react native with formik and yup.According to the documentation I have added the react native picker.
<Formik
initialValues={{ password: '', first_name: '', email: '', passwordConfirmation: '' }}
onSubmit={values => handleSubmit(values)}
validationSchema={registerSchema}
>
{({ handleChange, handleBlur, handleSubmit, values, touched, errors }) => (
<View>
<TextInput
style={styles.textInputTop}
onChangeText={handleChange('first_name')}
onBlur={handleBlur('first_name')}
value={values.first_name}
label="First Name"
mode="outlined"
/>
<Text style={styles.errorMsg}>{touched.first_name && errors.first_name}</Text>
//Other Fields I have not mentioned in the code
<View style={styles.pickerContainer}>
<Text style={styles.depText}>Department</Text>
<Picker
style={{ height: 50, width: 150 }}
onValueChange={(itemValue, itemIndex) => setdepartment(itemValue)}
mode={"dropdown"}
>
<Picker.Item label="Management" value="Management" />
<Picker.Item label="HR" value="HR" />
<Picker.Item label="Accounting" value="Accounting" />
<Picker.Item label="Sales" value="Sales" />
</Picker>
</View>
<Button style={styles.btn} mode="contained" onPress={handleSubmit}>
<Text style={{ color: "white" }}>Sign Up</Text>
</Button>
</View>
)}
</Formik>
I need to add formik and yup to the picker to make it a required field. How do I do it?
If it is not possible with formik and yup, then how I can make the picker required.

Answer 1

on the registerSchema make:
department: Yup.string().required('this field is required')
department will hold the selected value from the picker, you may change the type from string to array depending on the selected value.