Expressive TypeScript

Quick Guide: Write code that communicates its intent without requiring the reader to mentally simulate any of its parts. Apply the two-tier pattern: orchestrators at the top that read like pseudocode, pure functions at the bottom that each do one thing. Extract until the code reads like prose. Use utility libraries only when they genuinely improve readability over plain JS.

<critical_requirements>

CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST structure every non-trivial function as a two-tier orchestrator: guard clauses at the top, named function calls in the middle, assembly at the bottom -- NO inline data transformations in orchestrators)

(You MUST extract any expression that requires mental simulation to understand into a named function or named constant)

(You MUST name functions for WHAT they do, not HOW they do it -- isContentAddition(line) not checkLineStartsWithPlusButNotTriplePlus(line))

(You MUST read the existing code before refactoring -- understand the current structure, then improve it)