dot-skills Fog of War (JavaScript/TypeScript) Best Practices

Performance and correctness guide for fog of war and field-of-view systems in JS/TS games, distilled from the canonical FOV literature (Björn Bergström, Albert Ford, Adam Milazzo), Red Blob Games, rot.js, and the MDN/WebGL rendering APIs. Contains 44 rules across 8 categories, ordered by impact, to guide writing, reviewing, and refactoring visibility code.

When to Apply

Reference these guidelines when:

• Implementing field of view, line of sight, or tile visibility for a grid or continuous map
• Building or refactoring a fog-of-war display (unexplored / explored / visible layers)
• Diagnosing slow fog (recompute every frame), visual artifacts (flicker, light leaks), or memory blowups on large maps
• Scaling visibility to many units (RTS) or to large/streaming worlds
• Choosing how to store and render the visibility/explored state

Rule Categories by Priority