const data = '{"name": "Maria", "age": 25, "skills": ["JavaScript", "Python"]}';

try {
  const parsed = JSON.parse(data);
  const modified = {
    ...parsed,
    age: parsed.age + 5,
    skills: [...parsed.skills, "TypeScript"]
  };
  
  const serialized = JSON.stringify(modified, null, 0);
  const reparsed = JSON.parse(serialized);
  
  console.log(reparsed.skills.length);
  console.log(typeof reparsed.age);
} catch (error) {
  console.log('Parse error');
}