From posthog-pack
Sets up PostHog local dev workflow with debug mode, posthog-node mocking for unit tests, posthog-js browser debugging, and dev project integration.
How this skill is triggered — by the user, by Claude, or both
Slash command
/posthog-pack:posthog-local-dev-loopThis skill is limited to the following tools:
The summary Claude sees in its skill listing — used to decide when to auto-load this skill
Set up a fast local development workflow for PostHog integrations. Covers debug mode for event inspection, mocking posthog-node for unit tests, and a dev/test PostHog project to avoid polluting production data.
Set up a fast local development workflow for PostHog integrations. Covers debug mode for event inspection, mocking posthog-node for unit tests, and a dev/test PostHog project to avoid polluting production data.
posthog-install-auth setupmy-posthog-app/
├── src/
│ ├── analytics/
│ │ ├── posthog.ts # Singleton client
│ │ ├── events.ts # Event taxonomy (typed constants)
│ │ └── flags.ts # Feature flag keys
│ └── index.ts
├── tests/
│ ├── analytics.test.ts # Unit tests with mocked PostHog
│ └── integration.test.ts # Integration tests (real PostHog dev project)
├── .env.local # Dev keys (git-ignored)
├── .env.example # Template: NEXT_PUBLIC_POSTHOG_KEY=phc_...
└── package.json
// src/analytics/posthog.ts
import { PostHog } from 'posthog-node';
let client: PostHog | null = null;
export function getPostHog(): PostHog {
if (!client) {
client = new PostHog(process.env.NEXT_PUBLIC_POSTHOG_KEY!, {
host: process.env.POSTHOG_HOST || 'https://us.i.posthog.com',
flushAt: process.env.NODE_ENV === 'development' ? 1 : 20,
flushInterval: process.env.NODE_ENV === 'development' ? 0 : 10000,
// In dev, flush immediately so events appear instantly in dashboard
});
}
return client;
}
export async function shutdown() {
if (client) {
await client.shutdown();
client = null;
}
}
// Enable PostHog debug mode in development
import posthog from 'posthog-js';
posthog.init(process.env.NEXT_PUBLIC_POSTHOG_KEY!, {
api_host: 'https://us.i.posthog.com',
loaded: (ph) => {
if (process.env.NODE_ENV === 'development') {
ph.debug();
// All events logged to browser console:
// [PostHog.js] Sending event: {"event":"$pageview","properties":{...}}
}
},
});
// Disable capture entirely in test environments
if (process.env.NODE_ENV === 'test') {
posthog.opt_out_capturing();
}
// tests/analytics.test.ts
import { describe, it, expect, vi, beforeEach } from 'vitest';
// Mock posthog-node
vi.mock('posthog-node', () => {
const mockCapture = vi.fn();
const mockIdentify = vi.fn();
const mockGetFeatureFlag = vi.fn().mockResolvedValue(true);
const mockShutdown = vi.fn().mockResolvedValue(undefined);
const mockFlush = vi.fn().mockResolvedValue(undefined);
return {
PostHog: vi.fn().mockImplementation(() => ({
capture: mockCapture,
identify: mockIdentify,
getFeatureFlag: mockGetFeatureFlag,
getAllFlags: vi.fn().mockResolvedValue({ 'new-feature': true }),
shutdown: mockShutdown,
flush: mockFlush,
})),
};
});
import { PostHog } from 'posthog-node';
describe('Analytics', () => {
let ph: InstanceType<typeof PostHog>;
beforeEach(() => {
vi.clearAllMocks();
ph = new PostHog('phc_test_key');
});
it('captures events with correct properties', () => {
ph.capture({
distinctId: 'user-1',
event: 'button_clicked',
properties: { button: 'signup' },
});
expect(ph.capture).toHaveBeenCalledWith({
distinctId: 'user-1',
event: 'button_clicked',
properties: { button: 'signup' },
});
});
it('evaluates feature flags', async () => {
const result = await ph.getFeatureFlag('new-feature', 'user-1');
expect(result).toBe(true);
});
});
// tests/integration.test.ts
import { describe, it, expect, afterAll } from 'vitest';
import { PostHog } from 'posthog-node';
const POSTHOG_KEY = process.env.POSTHOG_TEST_KEY;
describe.skipIf(!POSTHOG_KEY)('PostHog Integration', () => {
const ph = new PostHog(POSTHOG_KEY!, {
host: 'https://us.i.posthog.com',
flushAt: 1,
flushInterval: 0,
});
afterAll(async () => {
await ph.shutdown();
});
it('should capture and flush an event', async () => {
ph.capture({
distinctId: `test-${Date.now()}`,
event: 'integration_test',
properties: { test: true },
});
// Flush returns successfully if network is reachable
await expect(ph.flush()).resolves.not.toThrow();
});
it('should evaluate feature flags', async () => {
const flags = await ph.getAllFlags(`test-${Date.now()}`);
expect(typeof flags).toBe('object');
});
});
{
"scripts": {
"dev": "tsx watch src/index.ts",
"test": "vitest run",
"test:watch": "vitest --watch",
"test:integration": "POSTHOG_TEST_KEY=$NEXT_PUBLIC_POSTHOG_KEY vitest run tests/integration"
}
}
| Error | Cause | Solution |
|---|---|---|
| Events not in dev dashboard | Wrong project key | Verify .env.local has dev project phc_ key |
| Mock not intercepting | Wrong import path | Ensure vi.mock path matches actual import |
| Integration test timeout | PostHog unreachable | Check network, increase vitest timeout |
| Debug mode too noisy | ph.debug() in prod | Guard with NODE_ENV === 'development' |
See posthog-sdk-patterns for production-ready code patterns.
npx claudepluginhub jeremylongshore/claude-code-plugins-plus-skills --plugin posthog-packGenerates minimal PostHog examples for event capture, identify, and feature flags using posthog-js (browser/React) and posthog-node (Node.js). For quick starts, testing, or learning SDK patterns.
Add PostHog SDK integration to any application: install package, initialize client, set up provider, and identify users.
Creates, edits, and optimizes skills for Claude Code, including drafting, evaluating with test prompts, iterating on performance, and improving skill descriptions for better triggering accuracy.