[fieldName, ...otherFieldNames].includes('email'), get: (fieldName: string) => (fieldName === 'email' ? 'Email already exists.' : undefined), }, }, }} /> @mit.edu) nor a Berkeley (@berkeley.edu) email.', }, }, }, }} /> Service Terms of Use", }, }, }, }} /> fieldName === 'termsAccepted', get: (fieldName: string) => (fieldName === 'termsAccepted' ? 'You must accept the terms.' : undefined), }, }, }} /> ['username', 'email'].includes(fieldName), get: (fieldName: string) => { if (fieldName === 'username') return 'Username is required.'; if (fieldName === 'email') return 'Invalid email format.'; }, }, }, }} />