Angular

Last updated:

|Edit this page

On this page

PostHog makes it easy to get data about traffic and usage of your Angular app. Integrating PostHog into your site enables analytics about user behavior, custom events capture, session recordings, feature flags, and more.

This guide walks you through integrating PostHog into your Angular app using the JavaScript Web SDK.

Installation

Install posthog-js using your package manager:

Terminal
yarn add posthog-js
# or
npm install --save posthog-js

In your src/main.ts, initialize PostHog using your project API key and instance address. You can find both in your project settings.

main.ts
import { bootstrapApplication } from '@angular/platform-browser';
import { appConfig } from './app/app.config';
import { AppComponent } from './app/app.component';
import posthog from 'posthog-js'


posthog.init(
  '<ph_project_api_key>',
  {
    api_host:'https://us.i.posthog.com',
    person_profiles: 'identified_only'
  }
)


bootstrapApplication(AppComponent, appConfig)
  .catch((err) => console.error(err));

Capture custom events

To capture custom events, import posthog and call posthog.capture(). Below is an example of how to do this in a component:

app.component.ts
import { Component } from '@angular/core';
import posthog from 'posthog-js'


@Component({
 // existing component code
})


export class AppComponent {
  handleClick() {
    posthog.capture(
      'home_button_clicked', 
    )
  }
}

Tracking pageviews

PostHog only captures pageview events when a page load is fired. Since Angular creates a single-page app, this only happens once, and the Angular router handles subsequent page changes.

If we want to capture every route change, we must write code to capture pageviews that integrates with the router.

To start, we need to add capture_pageview: false to the PostHog initialization to avoid double capturing the first pageview.

main.ts
import { bootstrapApplication } from '@angular/platform-browser';
import { appConfig } from './app/app.config';
import { AppComponent } from './app/app.component';
import posthog from 'posthog-js'


posthog.init(
  '<ph_project_api_key>',
  {
    api_host:'https://us.i.posthog.com',
    person_profiles: 'identified_only',
    capture_pageview: false
  }
)


bootstrapApplication(AppComponent, appConfig)
  .catch((err) => console.error(err));

Next, depending on your Angular version, add the following code to track pageviews:

Tracking pageviews in Angular v17 and above

Import the following in app.component.ts:

  1. posthog
  2. Router, Event, and NavigationEnd from @angular/router
  3. Observable from rxjs and filter from rxjs/operators

With these, we set up a subscription to the router events that captures a $pageview event on every NavigationEnd event:

app.component.ts
import { Component } from '@angular/core';
import { RouterOutlet, Router, Event, NavigationEnd } from '@angular/router';
import { filter } from 'rxjs/operators';
import { Observable } from 'rxjs';
import posthog from 'posthog-js';


@Component({
  selector: 'app-root',
  standalone: true,
  imports: [RouterOutlet],
  templateUrl: './app.component.html',
  styleUrl: './app.component.css'
})
export class AppComponent {
  title = 'angular-spa';


  navigationEnd: Observable<NavigationEnd>;


  constructor(public router: Router) {
    this.navigationEnd = router.events.pipe(
      filter((event: Event) => event instanceof NavigationEnd)
    ) as Observable<NavigationEnd>;
  }


  ngOnInit() {
    this.navigationEnd.subscribe((event: NavigationEnd) => {
      posthog.capture('$pageview');
    });
  }
}

Tracking pageviews in Angular v16 and below

To track pageviews in Angular v16 and below, import posthog into app-routing.module.ts, subscribe to router events and then capture $pageview events on NavigationEnd events:

JavaScript
// other imports...
import { RouterModule, Routes, Router, NavigationEnd } from '@angular/router';
import posthog from 'posthog-js';


//... routes, @NgModule


export class AppRoutingModule {
  constructor(private router: Router) {
    this.router.events.subscribe(event => {
      if (event instanceof NavigationEnd) {
        posthog.capture('$pageview');
      }
    });
  }
 }

Now, every time a user moves between pages, PostHog captures a $pageview event, not just on the first page load.

Capturing pageleaves

Setting capture_pageview: false also disables automatic pageleave capture. To re-enable this, add capture_pageleave: true to your PostHog initialization.

main.ts
import { bootstrapApplication } from '@angular/platform-browser';
import { appConfig } from './app/app.config';
import { AppComponent } from './app/app.component';
import posthog from 'posthog-js'


posthog.init(
  '<ph_project_api_key>',
  {
    api_host:'https://us.i.posthog.com',
    person_profiles: 'identified_only',
    capture_pageview: false,
    capture_pageleave: true
  }
)


bootstrapApplication(AppComponent, appConfig)
  .catch((err) => console.error(err));

Session replay

Session replay uses change detection to record the DOM. This can clash with Angular's change detection.

The recorder tool attempts to detect when an Angular zone is present and avoid the clash but might not always succeed.

If you see performance impact from recording in an Angular project, ensure that you use ngZone.runOutsideAngular.

posthog.service.ts
import { Injectable } from '@angular/core';
import posthog from 'posthog-js'


@Injectable({ providedIn: 'root' })
export class PostHogSessionRecordingService {
  constructor(private ngZone: NgZone) {}
initPostHog() {
    this.ngZone.runOutsideAngular(() => {
      posthog.init(
        /* your config */
      )
    })
  }
}

Next steps

For any technical questions for how to integrate specific PostHog features into Angular (such as feature flags, A/B testing, surveys, etc.), have a look at our JavaScript Web SDK docs.

Alternatively, the following tutorials can help you get started:

Questions?

Was this page useful?

Next article

Astro

PostHog makes it easy to get data about traffic and usage of your Astro app. Integrating PostHog into your site enables analytics about user behavior, custom events capture, session recordings, feature flags, and more. This guide walks you through integrating PostHog into your Astro app using the JavaScript Web SDK . Installation In your src/components folder, create a posthog.astro file: In this file, add your Web snippet which you can find in your project settings . Be sure to…

Read next article