ReddRadar
Agent skill
formik-patterns
Formik form handling with validation patterns. Use when building forms, implementing validation, or handling form submission.
Install this agent skill to your Project
npx add-skill https://github.com/aiskillstore/marketplace/tree/main/skills/chriswiles/formik-patterns
SKILL.md
Formik Patterns
Basic Form Setup
import { useFormik } from 'formik';
import * as yup from 'yup';
const validationSchema = yup.object({
email: yup.string().email('Invalid email').required('Email is required'),
password: yup.string().min(8, 'Min 8 characters').required('Password is required'),
});
const LoginForm = () => {
const formik = useFormik({
initialValues: {
email: '',
password: '',
},
validationSchema,
onSubmit: async (values) => {
await loginMutation({ variables: { input: values } });
},
});
return (
<VStack gap="$4">
<Input
label="Email"
value={formik.values.email}
onChangeText={formik.handleChange('email')}
onBlur={formik.handleBlur('email')}
error={formik.touched.email ? formik.errors.email : undefined}
keyboardType="email-address"
autoCapitalize="none"
/>
<Input
label="Password"
value={formik.values.password}
onChangeText={formik.handleChange('password')}
onBlur={formik.handleBlur('password')}
error={formik.touched.password ? formik.errors.password : undefined}
secureTextEntry
/>
<Button
onPress={formik.handleSubmit}
isDisabled={!formik.isValid || formik.isSubmitting}
isLoading={formik.isSubmitting}
>
Login
</Button>
</VStack>
);
};
Validation Schemas
Common Patterns
import * as yup from 'yup';
// Email
email: yup.string()
.email('Invalid email address')
.required('Email is required')
// Password with requirements
password: yup.string()
.min(8, 'Must be at least 8 characters')
.matches(/[a-z]/, 'Must contain lowercase letter')
.matches(/[A-Z]/, 'Must contain uppercase letter')
.matches(/[0-9]/, 'Must contain number')
.required('Password is required')
// Confirm password
confirmPassword: yup.string()
.oneOf([yup.ref('password')], 'Passwords must match')
.required('Please confirm password')
// Phone number
phone: yup.string()
.matches(/^\+?[1-9]\d{1,14}$/, 'Invalid phone number')
.required('Phone is required')
// Optional field with validation when present
website: yup.string()
.url('Must be a valid URL')
.nullable()
// Number with range
quantity: yup.number()
.min(1, 'Minimum 1')
.max(100, 'Maximum 100')
.required('Quantity required')
// Array with minimum items
tags: yup.array()
.of(yup.string())
.min(1, 'Select at least one tag')
Conditional Validation
const schema = yup.object({
hasCompany: yup.boolean(),
companyName: yup.string().when('hasCompany', {
is: true,
then: (schema) => schema.required('Company name required'),
otherwise: (schema) => schema.nullable(),
}),
});
Form Field Helpers
Input Helper
const getFieldProps = (name: keyof typeof formik.values) => ({
value: formik.values[name],
onChangeText: formik.handleChange(name),
onBlur: formik.handleBlur(name),
error: formik.touched[name] ? formik.errors[name] : undefined,
});
// Usage
<Input label="Email" {...getFieldProps('email')} />
Select/Picker Helper
<Select
label="Country"
value={formik.values.country}
onValueChange={(value) => formik.setFieldValue('country', value)}
error={formik.touched.country ? formik.errors.country : undefined}
options={countryOptions}
/>
Form Submission with GraphQL
const CreateItemForm = () => {
const [createItem] = useCreateItemMutation({
onCompleted: () => {
toast.success({ title: 'Item created' });
navigation.goBack();
},
onError: (error) => {
console.error('createItem failed:', error);
toast.error({ title: 'Failed to create item' });
},
});
const formik = useFormik({
initialValues: { name: '', description: '' },
validationSchema,
onSubmit: async (values, { setSubmitting }) => {
try {
await createItem({ variables: { input: values } });
} finally {
setSubmitting(false);
}
},
});
return (
<VStack gap="$4">
{/* Form fields */}
<Button
onPress={formik.handleSubmit}
isDisabled={!formik.isValid || formik.isSubmitting}
isLoading={formik.isSubmitting}
>
Create
</Button>
</VStack>
);
};
Edit Form with Initial Values
const EditItemForm = ({ item }: { item: Item }) => {
const [updateItem] = useUpdateItemMutation({
onCompleted: () => toast.success({ title: 'Saved' }),
onError: (error) => {
console.error('updateItem failed:', error);
toast.error({ title: 'Save failed' });
},
});
const formik = useFormik({
initialValues: {
name: item.name,
description: item.description ?? '',
},
enableReinitialize: true, // Update when item prop changes
validationSchema,
onSubmit: async (values) => {
await updateItem({
variables: { id: item.id, input: values },
});
},
});
// Track if form has changes
const hasChanges = formik.dirty;
return (
<VStack gap="$4">
{/* Form fields */}
<Button
onPress={formik.handleSubmit}
isDisabled={!hasChanges || !formik.isValid || formik.isSubmitting}
isLoading={formik.isSubmitting}
>
Save Changes
</Button>
</VStack>
);
};
Form State Helpers
const {
values, // Current form values
errors, // Validation errors
touched, // Fields that have been touched
isValid, // Form passes validation
isSubmitting, // Submit in progress
dirty, // Values differ from initial
handleSubmit, // Submit handler
handleChange, // Change handler
handleBlur, // Blur handler
setFieldValue, // Set single field
setFieldTouched, // Mark field touched
resetForm, // Reset to initial values
setSubmitting, // Control submitting state
} = formik;
Multi-Step Forms
const MultiStepForm = () => {
const [step, setStep] = useState(0);
const formik = useFormik({
initialValues: {
// Step 1
name: '',
email: '',
// Step 2
address: '',
city: '',
// Step 3
cardNumber: '',
},
validationSchema: stepSchemas[step],
onSubmit: async (values) => {
if (step < steps.length - 1) {
setStep(step + 1);
} else {
await submitOrder(values);
}
},
});
return (
<VStack>
{step === 0 && <PersonalInfoStep formik={formik} />}
{step === 1 && <AddressStep formik={formik} />}
{step === 2 && <PaymentStep formik={formik} />}
<HStack gap="$4">
{step > 0 && (
<Button variant="outline" onPress={() => setStep(step - 1)}>
Back
</Button>
)}
<Button
onPress={formik.handleSubmit}
isDisabled={!formik.isValid}
isLoading={formik.isSubmitting}
>
{step < steps.length - 1 ? 'Next' : 'Submit'}
</Button>
</HStack>
</VStack>
);
};
Anti-Patterns
// WRONG - Not showing validation errors
<Input
value={formik.values.email}
onChangeText={formik.handleChange('email')}
/>
// CORRECT - Show errors when touched
<Input
value={formik.values.email}
onChangeText={formik.handleChange('email')}
onBlur={formik.handleBlur('email')}
error={formik.touched.email ? formik.errors.email : undefined}
/>
// WRONG - Submit button always enabled
<Button onPress={formik.handleSubmit}>Submit</Button>
// CORRECT - Disabled when invalid or submitting
<Button
onPress={formik.handleSubmit}
isDisabled={!formik.isValid || formik.isSubmitting}
isLoading={formik.isSubmitting}
>
Submit
</Button>
// WRONG - No error handling on mutation
onSubmit: async (values) => {
await createItem({ variables: { input: values } });
}
// CORRECT - Handle errors
onSubmit: async (values, { setSubmitting }) => {
try {
await createItem({ variables: { input: values } });
} catch (error) {
toast.error({ title: 'Failed to save' });
} finally {
setSubmitting(false);
}
}
Integration with Other Skills
- graphql-schema: Mutation submission patterns
- react-ui-patterns: Loading/error states
- testing-patterns: Test form validation and submission
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
aiskillstore/marketplace
perigon-backend
Perigon ASP.NET Core + EF Core + Aspire conventions
aiskillstore/marketplace
perigon-agent
Pointers for Copilot/agents to apply Perigon conventions
aiskillstore/marketplace
perigon-angular
Angular 21+ standalone/Material/signal conventions for Perigon WebApp
aiskillstore/marketplace
fastapi-mastery
Comprehensive FastAPI development skill covering REST API creation, routing, request/response handling, validation, authentication, database integration, middleware, and deployment. Use when working with FastAPI projects, building APIs, implementing CRUD operations, setting up authentication/authorization, integrating databases (SQL/NoSQL), adding middleware, handling WebSockets, or deploying FastAPI applications. Triggered by requests involving .py files with FastAPI code, API endpoint creation, Pydantic models, or FastAPI-specific features.
aiskillstore/marketplace
context7-efficient
Token-efficient library documentation fetcher using Context7 MCP with 86.8% token savings through intelligent shell pipeline filtering. Fetches code examples, API references, and best practices for JavaScript, Python, Go, Rust, and other libraries. Use when users ask about library documentation, need code examples, want API usage patterns, are learning a new framework, need syntax reference, or troubleshooting with library-specific information. Triggers include questions like "Show me React hooks", "How do I use Prisma", "What's the Next.js routing syntax", or any request for library/framework documentation.
aiskillstore/marketplace
browser-use
Browser automation using Playwright MCP. Navigate websites, fill forms, click elements, take screenshots, and extract data. Use when tasks require web browsing, form submission, web scraping, UI testing, or any browser interaction.
Didn't find tool you were looking for?