javascript-testing-patterns

A guide to testing JavaScript and TypeScript applications, including tests for individual functions, connected services, user flows, and user-interface components. It also covers TDD, where tests are written before the code they check.

In plain words
What is it for?
Use it to set up test projects, write unit, integration, and end-to-end tests, mock external APIs, test React or Vue components, and add testing to CI/CD.
Why use it?
It helps choose suitable tests, handle outside services safely, and verify that changes continue to work in automated builds.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/kunanonj/ai-skills-hub/javascript-testing-patterns
Any agent
npx skills add KunanonJ/ai-skills-hub --skill javascript-testing-patterns
Clone the repo
git clone --depth 1 https://github.com/KunanonJ/ai-skills-hub

Made for: Claude Code, Codex.

Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 320 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00028 $0.00320
Opus 5 $0.00014 $0.00160
Sonnet 5 $0.00006 $0.00064
Haiku 4.5 $0.00003 $0.00032

Measured 2d ago against content hash 9aebe35bdcf5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

javascript-testing-patterns scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/javascript-testing-patterns/SKILL.md · 44 lines

What it actually says

JavaScript Testing Patterns

Comprehensive guide for implementing robust testing strategies in JavaScript/TypeScript applications using modern testing frameworks and best practices.

Use this skill when

  • Setting up test infrastructure for new projects
  • Writing unit tests for functions and classes
  • Creating integration tests for APIs and services
  • Implementing end-to-end tests for user flows
  • Mocking external dependencies and APIs
  • Testing React, Vue, or other frontend components
  • Implementing test-driven development (TDD)
  • Setting up continuous testing in CI/CD pipelines

Do not use this skill when

  • The task is unrelated to javascript testing patterns
  • You need a different domain or tool outside this scope

Instructions

  • Clarify goals, constraints, and required inputs.
  • Apply relevant best practices and validate outcomes.
  • Provide actionable steps and verification.
  • If detailed examples are required, open resources/implementation-playbook.md.

Resources

  • resources/implementation-playbook.md for detailed patterns and examples.

Limitations

  • Use this skill only when the task clearly matches the scope described above.
  • Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
  • Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 44 lines · 28 tokens per session scan A 9aebe35bdcf5

Subscribe to this mod's changes

javascript-testing-patterns is a skill published in the GitHub repository KunanonJ/ai-skills-hub (4 stars, last pushed 1mo ago), licensed MIT. It adds 28 tokens to every session and 320 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.