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| import { useState, useCallback } from 'react';
function useForm(initialValues, validationRules = {}) {
const [values, setValues] = useState(initialValues);
const [errors, setErrors] = useState({});
const [touched, setTouched] = useState({});
const validateField = useCallback((name, value) => {
const rules = validationRules[name];
if (!rules) return '';
for (const rule of rules) {
const error = rule(value, values);
if (error) return error;
}
return '';
}, [validationRules, values]);
const validateAll = useCallback(() => {
const newErrors = {};
Object.keys(validationRules).forEach(name => {
const error = validateField(name, values[name]);
if (error) {
newErrors[name] = error;
}
});
setErrors(newErrors);
return Object.keys(newErrors).length === 0;
}, [validationRules, values, validateField]);
const handleChange = useCallback((name, value) => {
setValues(prev => ({ ...prev, [name]: value }));
if (touched[name]) {
const error = validateField(name, value);
setErrors(prev => ({ ...prev, [name]: error }));
}
}, [touched, validateField]);
const handleBlur = useCallback((name) => {
setTouched(prev => ({ ...prev, [name]: true }));
const error = validateField(name, values[name]);
setErrors(prev => ({ ...prev, [name]: error }));
}, [values, validateField]);
const reset = useCallback(() => {
setValues(initialValues);
setErrors({});
setTouched({});
}, [initialValues]);
const handleSubmit = useCallback((onSubmit) => {
return (event) => {
event.preventDefault();
const allTouched = Object.keys(validationRules).reduce((acc, key) => {
acc[key] = true;
return acc;
}, {});
setTouched(allTouched);
if (validateAll()) {
onSubmit(values);
}
};
}, [values, validationRules, validateAll]);
return {
values,
errors,
touched,
handleChange,
handleBlur,
handleSubmit,
reset,
isValid: Object.keys(errors).length === 0
};
}
const required = (message = 'This field is required') => (value) => {
return !value || value.trim() === '' ? message : '';
};
const email = (message = 'Invalid email format') => (value) => {
const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
return value && !emailRegex.test(value) ? message : '';
};
const minLength = (min, message) => (value) => {
return value && value.length < min ? message || `Minimum length is ${min}` : '';
};
function ContactForm() {
const {
values,
errors,
touched,
handleChange,
handleBlur,
handleSubmit,
reset,
isValid
} = useForm(
{
name: '',
email: '',
message: ''
},
{
name: [required('Name is required')],
email: [
required('Email is required'),
email('Please enter a valid email')
],
message: [
required('Message is required'),
minLength(10, 'Message must be at least 10 characters')
]
}
);
const onSubmit = (formData) => {
console.log('Form submitted:', formData);
reset();
};
return (
<form onSubmit={handleSubmit(onSubmit)}>
<div className="form-group">
<label htmlFor="name">Name:</label>
<input
id="name"
type="text"
value={values.name}
onChange={(e) => handleChange('name', e.target.value)}
onBlur={() => handleBlur('name')}
className={errors.name && touched.name ? 'error' : ''}
/>
{errors.name && touched.name && (
<span className="error-message">{errors.name}</span>
)}
</div>
<div className="form-group">
<label htmlFor="email">Email:</label>
<input
id="email"
type="email"
value={values.email}
onChange={(e) => handleChange('email', e.target.value)}
onBlur={() => handleBlur('email')}
className={errors.email && touched.email ? 'error' : ''}
/>
{errors.email && touched.email && (
<span className="error-message">{errors.email}</span>
)}
</div>
<div className="form-group">
<label htmlFor="message">Message:</label>
<textarea
id="message"
value={values.message}
onChange={(e) => handleChange('message', e.target.value)}
onBlur={() => handleBlur('message')}
className={errors.message && touched.message ? 'error' : ''}
/>
{errors.message && touched.message && (
<span className="error-message">{errors.message}</span>
)}
</div>
<div className="form-actions">
<button type="submit" disabled={!isValid}>Submit</button>
<button type="button" onClick={reset}>Reset</button>
</div>
</form>
);
}
|
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