Cursor – How to Improve Your Code from ‘Just Write’ to ‘Write Well’

Hello everyone! Today we will talk about a topic that many developers care about: how to write better code.

Recently, while using Cursor, I found that it not only helps us write code quickly but more importantly, it helps us improve code quality. Here are some in-depth usage tips.

The Art of Code Refactoring

From Chaos to Clarity

Take a look at this common business code:

function handleUserData(data) {
    if(data) {
        const result = [];
        for(let i = 0; i < data.length; i++) {
            if(data[i].status === 'active') {
                result.push({
                    name: data[i].name,
                    age: data[i].age,
                    score: data[i].points * 2
                });
            }
        }
        return result;
    }
    return [];
}

Let Cursor help us refactor: “How can this code be rewritten in a functional programming way to make it clearer?”

The optimized code is:

const handleUserData = (data = []) => 
    data
        .filter(user => user.status === 'active')
        .map(user => ({
            name: user.name,
            age: user.age,
            score: user.points * 2
        }));

Performance Optimization

Now let’s look at this component:

function UserDashboard() {
    const [users, setUsers] = useState([]);
    const [stats, setStats] = useState({});
    
    useEffect(() => {
        fetchUsers().then(setUsers);
        fetchStats().then(setStats);
    }, []);

    const processedData = users.map(user => ({
        ...user,
        score: calculateScore(user)
    }));

    return (
        <div>
            {processedData.map(user => (
                <usercard key="{user.id}" user="{user}"></usercard>
            ))}
        </div>
    );
}

Ask Cursor: “What performance issues does this component have? How can it be optimized?”

The optimized code is:

function UserDashboard() {
    const [users, setUsers] = useState([]);
    const [stats, setStats] = useState({});
    
    useEffect(() => {
        Promise.all([
            fetchUsers(),
            fetchStats()
        ]).then(([userData, statsData]) => {
            setUsers(userData);
            setStats(statsData);
        });
    }, []);

    const processedData = useMemo(() =>
        users.map(user => ({
            ...user,
            score: calculateScore(user)
        })),
        [users]
    );

    return (
        <div>
            {processedData.map(user => (
                <usercard key="{user.id}" stats="{stats[user.id]}" user="{user}"></usercard>
            ))}
        </div>
    );
}

Tips for Improving Code Quality

Error Handling

Don’t just simply catch errors:

async function fetchData() {
    try {
        const response = await api.getData();
        return response.data;
    } catch (error) {
        console.error('Error:', error);
        return null;
    }
}

Let Cursor help us improve error handling:

async function fetchData() {
    try {
        const response = await api.getData();
        if (!response.data) {
            throw new Error('No data received');
        }
        return response.data;
    } catch (error) {
        if (error.response) {
            // Server error
            logger.error('Server Error:', {
                status: error.response.status,
                data: error.response.data
            });
            throw new ApiError(error.response.data.message);
        } else if (error.request) {
            // Network error
            logger.error('Network Error:', error.request);
            throw new NetworkError('Network request failed');
        } else {
            // Other errors
            logger.error('Error:', error);
            throw new AppError('An unexpected error occurred');
        }
    }
}

Code Maintainability

Use Cursor to generate complete type definitions and documentation:

/**
 * User Data Processing Service
 * @class UserService
 */
class UserService {
    /**
     * Process user data
     * @param {UserData[]} users - Original user data
     * @returns {ProcessedUser[]} Processed user data
     * @throws {ValidationError} When the user data format is incorrect
     */
    processUsers(users: UserData[]): ProcessedUser[] {
        return users.map(this.transformUser);
    }

    /**
     * Transform a single user data
     * @private
     * @param {UserData} user - Original user data
     * @returns {ProcessedUser} Transformed user data
     */
    private transformUser(user: UserData): ProcessedUser {
        // Data transformation logic
    }
}

Improving Code Security

Data Validation

Do not trust input data blindly:

function processUserInput(data) {
    const schema = Joi.object({
        username: Joi.string().min(3).max(30).required(),
        email: Joi.string().email().required(),
        age: Joi.number().min(0).max(150)
    });

    const { error, value } = schema.validate(data);
    if (error) {
        throw new ValidationError(error.details[0].message);
    }

    return value;
}

Notes

Control Code Complexity

Single function should not exceed 30 lines
Nesting levels should not exceed 3
A file should not exceed 300 lines

Performance Considerations

Use caching appropriately
Avoid unnecessary re-renders
Optimize large data processing

Maintainability

Consistent coding style
Complete error handling
Clear comments and documentation

End

Writing good code is not something that happens overnight; it requires continuous accumulation and improvement. Cursor can help us reach this goal faster, but the key is to understand the principles behind each optimization.

Remember, improving code quality is a gradual process. The important thing is to maintain a learning mindset and continuously refine your skills.

How to Improve Your Code Quality with Cursor