What problem does it solve? TypeScript projects often accumulate inconsistent style, unsafe type casts, and weak tests because rules are scattered or undocumented. This Skill provides a single normative rule set covering type safety, control flow, testing, and coverage so every .ts, .tsx, .mts, and .cts change follows the same standard. ## Core Features & Use Cases - Normative rule set: 75 numbered rules covering types (no any, no as, satisfies over as const), functions (DRY, guards, minimal nesting), and modules (no barrel files, no import * as). - Test and coverage enforcement: Mandates colocated *.test.ts files, 80-90% coverage targets, strict assertions (toStrictEqual, no toContain), and mocked I/O for fast tests. - Verification workflow: Requires bun run tsc, lint, and bun run test to pass after every change, with Oxlint/Oxfmt or Biome as the linting toolchain. - Use Case: When asked to add a feature to a Bun-based TypeScript service, the agent loads these rules and produces interface-first, enum-free code with colocated tests that pass type checking and lint cleanly. ## Quick Start Apply the TypeScript coding rules while implementing and testing the new feature in this Bun project.
