posthog-js

What is posthog-js?

The posthog-js npm package is a JavaScript library for integrating PostHog analytics into web applications. It allows you to track user interactions, capture events, and analyze user behavior in real-time.

What are posthog-js's main functionalities?

Initialization

Initialize the PostHog library with your API key and optional configuration settings.

const posthog = require('posthog-js');
posthog.init('YOUR_API_KEY', { api_host: 'https://app.posthog.com' });

Capture Events

Capture custom events with properties to track user interactions and behaviors.

posthog.capture('event_name', { property1: 'value1', property2: 'value2' });

Identify Users

Identify users with unique IDs and associate them with properties like email and name.

posthog.identify('user_id', { email: '[e-mail]', name: 'John Doe' });

Set User Properties

Set properties for identified users to enrich user profiles with additional information.

posthog.people.set({ property1: 'value1', property2: 'value2' });

Feature Flags

Check if a feature flag is enabled for the current user to implement feature toggling.

const isEnabled = posthog.isFeatureEnabled('feature_flag_key');

Other packages similar to posthog-js

mixpanel-browser

Mixpanel is a powerful analytics tool that offers similar functionalities to PostHog, such as event tracking, user identification, and property setting. Mixpanel also provides advanced features like A/B testing and user segmentation.

amplitude-js

Amplitude is an analytics platform focused on product intelligence. It offers event tracking, user identification, and behavioral analytics. Amplitude provides advanced features like cohort analysis and user journey mapping, which can be more detailed than PostHog's offerings.

README

PostHog.js

Please see the main PostHog docs.

Specifically, the JS integration details.

Testing

Unit tests: run yarn test Cypress: yarn cypress

Running TestCafe E2E tests with BrowserStack

Testing on IE11 requires a bit more setup.

1. Run posthog locally on port 8000
2. Run python manage.py setup_dev --no-data on posthog repo, which sets up a demo account
3. Optional: rebuild array.js on changes: nodemon -w src/ --exec bash -c "yarn build-array"
4. Export browserstack credentials: export BROWSERSTACK_USERNAME=xxx BROWSERSTACK_ACCESS_KEY=xxx
5. Run tests: npx testcafe "browserstack:ie" testcafe/e2e.spec.js

Developing together with another repo

Update dependency in package.json to e.g. "posthog-js": "link:../posthog-js", yarn and run yarn build && yarn build-module

Releasing a new version

To release a new version, make sure you're logged in to NPM (npm login)

We tend to follow the following steps:

1. Merge your changes into master
2. Release changes as a beta version
   • npm version 1.x.x-beta.0
   • npm publish --tag beta
   • git push --tags
3. Create a PR linking to this version in the main repo
4. Once deployed and tested, write up CHANGELOG.md, and commit.
5. Release a new version
   • npm version 1.x.x
   • npm publish
   • git push --tags
6. Create a PR linking to this version in the main repo

Questions?

Join our Slack community.

Changelog

1.9.6 - 2021-03-30

• Support rrweb mask all inputs (#207)
• fix: incorrect typing for isFeatureEnabled (#208)