Add Typescript Best Practices

Setup TypeScript best practices and code style rules in CLAUDE.md

Security Scan

The skill's instructions match its described purpose (writing TypeScript style guidance to CLAUDE.md), it requires no credentials or installs, and there are no scan findings — nothing appears disproportionate or hidden.

Purpose & Capability

The name and description (add TypeScript best practices into CLAUDE.md) align with the SKILL.md content, which instructs the agent to create or update CLAUDE.md with the provided rules. The skill does not request unrelated capabilities.

Instruction Scope

The SKILL.md instructs the agent to write the provided markdown exactly as-is into a file named CLAUDE.md. That means the skill will create or overwrite a repository file; the instruction is narrowly scoped and does not ask the agent to read other files, access environment variables, or send data externally. User beware: it may overwrite existing CLAUDE.md content. The content is opinionated style guidance but contains no external endpoints or secrets.

Install Mechanism

No install spec is present (instruction-only), so nothing is downloaded or written to disk by an installer step. This is the lowest-risk install model.

Credentials

The skill requests no environment variables, credentials, or config paths. The guidance references common libraries by name but does not require access to package registries or keys.

Persistence & Privilege

always:false (default) and the skill does not request elevated or persistent privileges. It does modify project state by writing a file, but it does not alter other skills, agent configs, or request system-wide access.

Assessment

This skill simply writes opinionated TypeScript style guidance into a file named CLAUDE.md and does not request credentials or install anything. Before installing or running it, confirm where CLAUDE.md will be written (it may overwrite an existing file) and consider backing up or committing current changes. Review the exact markdown (it's enforced to be written verbatim) to ensure the wording and recommendations match your team's preferences.

Setup TypeScript Best Practices

Create or update CLAUDE.md in with following content, <critical>write it strictly as it is<critical>, do not summaraise or introduce and new additional information:

## Code Style Rules

### General Principles

- **TypeScript**: All code must be strictly typed, leverage TypeScript's type safety features

### Code style rules

- Interfaces over types - use interfaces for object types
- Use enum for constant values, prefer them over string literals
- Export all types by default
- Use type guards instead of type assertions

### Best Practices

#### Library-First Approach

- Common areas where libraries should be preferred:
  - Date/time manipulation → date-fns, dayjs
  - Form validation → joi, yup, zod
  - HTTP requests → axios, got
  - State management → Redux, MobX, Zustand
  - Utility functions → lodash, ramda

#### Code Quality

- Use destructuring of objects where possible:
  - Instead of `const name = user.name` use `const { name } = user`
  - Instead of `const result = await getUser(userId)` use `const { data: user } = await getUser(userId)`
  - Instead of `const parseData = (data) => data.name` use `const parseData = ({ name }) => name`
- Use `ms` package for time related configuration and environment variables, instead of multiplying numbers by 1000