add-strict-checks

majiayu000's avatarfrom majiayu000

Enable stricter TypeScript and linting checks to catch bugs early, especially useful when iterating with AI assistance.

⭐0stars🔀0forks📁View on GitHub🕐Updated Jan 5, 2026
[Testing and QA]

When & Why to Use This Skill

This Claude skill automates the process of hardening TypeScript projects by enabling strict compiler options and robust linting configurations. It is designed to enhance code reliability and catch potential bugs early in the development lifecycle by enforcing rigorous static analysis and type safety standards, which is particularly effective when collaborating with AI for rapid iteration.

Use Cases

  • Scenario 1: Hardening a legacy TypeScript codebase by incrementally enabling strict type-checking flags to identify and resolve hidden type mismatches.
  • Scenario 2: Setting up a standardized 'zero-warning' environment in new projects by integrating Biome linting and strict TypeScript rules from the start.
  • Scenario 3: Automating the remediation of linting and type errors through an iterative 'check-and-fix' loop to ensure the project meets high-quality production standards.
  • Scenario 4: Strengthening CI/CD and pre-commit workflows by adding mandatory type-check scripts to the project's core documentation and execution paths.
nameadd-strict-checks
description'Enable stricter TypeScript and linting checks to catch bugs early, especially useful when iterating with AI assistance.'

Add Strict Checks

Goal: Enable stricter TypeScript compiler options and linting to catch bugs that standard TypeScript misses.

Task 1: Add Stricter Compiler Options

Add these additional strict options to tsconfig.json under compilerOptions:

{
  "compilerOptions": {
    // ... existing options ...

    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "noImplicitOverride": true,
    "forceConsistentCasingInFileNames": true,
    "exactOptionalPropertyTypes": true,
    "useUnknownInCatchVariables": true
  }
}

Task 2: Add Check Script

Add a check script to package.json:

{
  "scripts": {
    "typecheck:app": "tsc --noEmit -p tsconfig.check.json",
    "typecheck:tests": "tsc --noEmit -p tsconfig.test.json",
    "check": "biome check . && npm run typecheck:app && npm run typecheck:tests"
  }
}

Task 3: Fix All Issues

Run npm run check:write && npm run check in a loop, fixing issues until it passes.

IMPORTANT: NEVER disable any checks:

  • NEVER disable any biome checks,
  • NEVER edit tsconfig.json to remove or disable a check
  • NEVER edit tsconfig.check.json to remove or disable a check
  • NEVER edit package.json to remove a check from a script

NEVER disable checks, even temporarily for any reason (including for easier work with third-party libraries)

Instead, fix the code to not violate the check.

Task 4: Update CLAUDE.md

Update the "Before Committing" section to include npm run check:

npm test && npm run check

If tests aren't set up yet, just use:

npm run check

Task 5: Commit

Ask the user if they want to commit the changes.

Task 6: Offer Further Hardening

Ask the user: "Would you like to add backend testing as well? This sets up integration tests with an isolated test database."

If yes, follow the add-backend-testing skill.