Code resources

Practical snippets and patterns

A curated set of reusable patterns for API work, Python, SQL, and React development.

TypeScriptAPI patterns

Fast JSON pagination with TypeScript

A reusable pattern for paginating API results with cursor-aware responses and safe defaults.

type PageResult<T> = {
  items: T[];
  nextCursor: string | null;
};

export async function fetchPage<T>(
  cursor: string | null,
  limit = 25,
): Promise<PageResult<T>> {
  const params = new URLSearchParams({ limit: String(limit) });
  if (cursor) params.set("cursor", cursor);

  const response = await fetch(`/api/items?${params.toString()}`);
  const data = (await response.json()) as { items: T[]; nextCursor?: string | null };

  return {
    items: data.items,
    nextCursor: data.nextCursor ?? null,
  };
}

PythonPython

Python list comprehension cheat sheet

Compact transformations for filtering and reshaping collections without verbose loops.

numbers = [1, 2, 3, 4, 5, 6]
squares = [n * n for n in numbers if n % 2 == 0]
print(squares)  # [4, 16, 36]

SQLSQL

SQL window functions for summaries

Aggregate values across rows while preserving the original record detail in each result.

SELECT
  customer_id,
  order_total,
  AVG(order_total) OVER (PARTITION BY customer_id) AS avg_customer_order
FROM orders;

ReactReact

React form validation pattern

Validate user input before submit, while surfacing inline errors and accessible feedback.

const [email, setEmail] = useState('');
const [error, setError] = useState('');

const handleSubmit = () => {
  const isValid = /^[^s@]+@[^s@]+.[^s@]+$/.test(email);
  setError(isValid ? '' : 'Enter a valid email address.');
};