turborepo-fixed-map

Purpose

Specialized map with fixed keys determined at construction. Provides thread-safe, one-time initialization of values for predefined keys.

Architecture

FixedMap<K, V>
    ├── Keys fixed at construction
    ├── Values initialized lazily (OnceLock)
    └── Thread-safe concurrent access

Operations:

• new(keys) - Create with known keys
• get(key) - Get value if initialized
• insert(key, value) - Initialize value (first write wins)

Notes

Used for lazy-loading turbo.json files. The fixed key set allows caching loaded configs while the OnceLock ensures thread-safe initialization. Values cannot be removed or overwritten once set.