Implements a BehaviorSubject/Observable pattern for reactive state management. Self-contained class that can be extracted into any JavaScript project for pub/sub or state change notifications. Demonstrates clean observable implementation with subscription management and value emission.

Provides safe nested property manipulation (set, setCopyOnWrite, unset) with protection against prototype pollution attacks. Standalone utility that can be reused in any JavaScript project for immutable state updates. Includes guards against __proto__ and constructor injection.

Deep object traversal with circular reference detection. Useful for cloning, serialization, or transformation of nested data structures. Self-contained and reusable across projects that need to walk complex object graphs safely.

Evaluates simple state binding expressions (e.g., 'state.x.y') without using eval or new Function, preventing code injection. Demonstrates a secure pattern for limited expression evaluation that can be extracted for any project needing safe dynamic property access.

Merges multiple GraphQL queries into a single request to reduce network calls. While Gatsby-specific in its current form, the algorithm for merging queries by type and field is a reusable pattern for any GraphQL batching scenario. Demonstrates thoughtful optimization for data fetching.