typescript-best-practices

What problem does it solve? TypeScript codebases accumulate unsafe patterns like any casts, lying type guards, and optional-field bags that hide bugs until runtime. This Skill enforces disciplined type-system practices whenever an agent reads or edits TypeScript files, and it refuses to guess when required inputs are missing. ## Core Features & Use Cases - Type-system discipline rules: Enforces discriminated unions, branded types, unknown over any, schema-derived types, and exhaustiveness checks via a structured rule table. - Intake and HOLD gates: Stops and reports missing inputs (no .ts/.tsx target, unreadable tsconfig) instead of inventing speculative types or rival house styles. - Cut-first defaults: Prefers existing project patterns and the smallest typing fix, refusing drive-by refactors and unrequested utility types. - Use Case: While editing a React component in a .tsx file, the Skill replaces an as cast with a zod schema parse at the boundary and adds an exhaustiveness check to a switch over a discriminated union. ## Quick Start Review the attached TypeScript file and apply type-system best practices, holding on anything that conflicts with the project tsconfig.