Vue.js

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

This guide walks you through integrating PostHog into your app for both Vue.js major versions 2 and 3. We'll use the JavaScript SDK.

For integrating PostHog into a Nuxt.js app, see our Nuxt guide.

Prerequisites

To follow this guide along, you need:

A PostHog account (either Cloud or self-hosted)
A running Vue.js application

Setting up PostHog

Install posthog-js using your package manager:

Terminal

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

Initializing PostHog

We cover four different methods for initializing PostHog:

Plugins
Provide/inject
Vue.prototype
Composition API

Choose what is best for you, considering your Vue version and your codebase’s stylistic choices.

Method 1: Create a Plugin

Note: For both Vue 3.x and Vue 2.x users

First, create a new file posthog.js in your plugins directory.

Terminal

mkdir plugins #skip if you already have one
cd plugins 
touch posthog.js

Next, create a plugin and assign PostHog to Vue’s global properties. The code will differ depending on your version of Vue.

Vue 3.x:

JavaScript

//./plugins/posthog.js
import posthog from "posthog-js";

export default {
  install(app) {
    app.config.globalProperties.$posthog = posthog.init(
      "<ph_project_api_key>",
      {
        api_host: "https://us.i.posthog.com",
        person_profiles: 'identified_only',
      }
    );
  },
};

Vue 2.x:

JavaScript

//./plugins/posthog.js
import posthog from "posthog-js";

export default {
  install(Vue, options) {
    Vue.prototype.$posthog = posthog.init(
      "<ph_project_api_key>",
      {
        api_host: "https://us.i.posthog.com",
        person_profiles: 'identified_only',
      }
    );
  }
};

Finally, activate your plugin in the file where you initialize your app. For Vue 3.x, it will likely be your index.js file. For Vue 2.x, it will be your main.js file.

Vue 3.x:

JavaScript

//main.js
import { createApp } from 'vue'
import App from './App.vue'
import posthogPlugin from "./plugins/posthog"; //import the plugin. 

const app = createApp(App);

app.use(posthogPlugin); //install the plugin
app.mount('#app')

Vue 2.x:

JavaScript

//main.js
import posthogPlugin from "./plugins/posthog"; // import the plugin

Vue.use(posthogPlugin); // install the plugin, before new Vue()

You can now use PostHog throughout your Vue app using this.$posthog. For example:

JavaScript

//component.vue

<script>
export default {
  data() {
    return {
      foo: "bar!",
    };
  },
  watch: {
    // whenever question changes, this function will run
    foo(newFoo, oldFoo) {
      this.$posthog.capture("foo_changed", {foo: newFoo});
    },
  },
  created() {
    console.log("Created", this.$posthog); //posthog accessible anywhere!
  },
};
</script>

Method 2: Use provide / inject

Note: For Vue 3.x users only

With Vue 3.x, developers can use provide() and inject() to pipe global values into any component without prop drilling. And if you don’t know what prop drilling is, good for you.

While this method is more declarative — as you need to inject PostHog into every component — it avoids “polluting” globals (like method 1 does). Some engineers prefer this approach, while others include PostHog in globals since it doesn’t need to be reactive and will be called throughout your application.

Step 1: Initialize Vue

Prior to mounting the app, you must:

Import PostHog
Initialize it
Provide it to your app.

This must be done before you mount my app. If I provide PostHog after mounting it, PostHog will not be predictably available.

JavaScript

//app.js

import posthog from "posthog-js";

const app = createApp(App);
posthog.init("<ph_project_api_key>", {
  api_host: "https://us.i.posthog.com",
  person_profiles: 'identified_only',
});
app.provide("posthog", posthog);

Step 2: Inject into any Vue file

JavaScript

//component.vue

export default {
  data() {
    return {
      greeting: "How are you!",
    };
  },
  inject: ["posthog"], //grab the injection from app-wide provider
  created() {
    console.log("Created", this.posthog); //posthog accessible!
  },
};

Method 3: Use Vue.prototype

Note: For Vue 2.x users only

While Vue 3.x dramatically clamped down on global variables, in Vue 2.x, you can initialize PostHog by using Object.defineProperty and Vue.prototype.

Anywhere, declare:

JavaScript

import posthog from "posthog-js";
Object.defineProperty(Vue.prototype, '$posthog', { value: posthog });

Then, access PostHog by calling this.$posthog.

JavaScript

//component.vue

export default {
  created() {
    this.$posthog.capture("app_created");
  }
}

Method 4: Use the Composition API

Create a new folder composables in your project. In that folder, create a new file usePosthog.js with the following initialization code:

JavaScript

// composables/usePostHog.js
import { provide, inject } from 'vue'
import posthog from 'posthog-js'

const PostHogSymbol = Symbol('PostHog')

export function usePostHogProvider() {
  const posthogInstance = posthog.init(
    "<ph_project_api_key>",
    {
      api_host: "https://us.i.posthog.com",
      person_profiles: 'identified_only'
    }
  )

  provide(PostHogSymbol, posthogInstance)

  return posthogInstance
}

export function usePostHog() {
  const posthogInstance = inject(PostHogSymbol)
  if (!posthogInstance) {
    throw new Error('PostHog has not been provided')
  }
  return posthogInstance
}

In App.vue, call usePostHogProvider() to initialize PostHog.

JavaScript

// ...rest of your app
</template>

<script setup>
import { usePostHogProvider } from './composables/usePostHog'

// Initialize and provide PostHog
usePostHogProvider()
</script>

<script>
// ...rest of your app

You can then use usePostHog() to access PostHog in any component.

JavaScript

<template>
  <div>
    <button @click="trackEvent">Track Event</button>
  </div>
</template>

<script setup>
import { usePostHog } from '../composables/usePostHog'

const posthog = usePostHog()

const trackEvent = () => {
  posthog.capture('button_clicked', { property: 'value' })
}
</script>

Capturing pageviews

You might notice that moving between pages only captures a single pageview event. This is because PostHog only captures pageview events when a page load is fired. Since Vue creates a single-page app, this only happens once, and the Vue 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.

First, make sure to set capture_pageview in the PostHog initialization config to false. This turns off autocaptured pageviews and ensures you won’t double-capture pageviews on the first load.

JavaScript

// in the file where you initialize posthog
posthog.init(
      "<ph_project_api_key>",
      {
        api_host: "https://us.i.posthog.com",
        person_profiles: 'identified_only',
        capture_pageview: false
      }
);

Vue 3.x:

In main.js, set up PostHog to capture pageviews in the router.afterEach function. Additionally, you can use nextTick so that the capture event fires only after the page is mounted.

JavaScript

// main.js
import { createApp, nextTick } from 'vue'
import App from './App.vue'
import router from './router'
import posthogPlugin from '../plugins/posthog';

const app = createApp(App);
app.use(posthogPlugin)
.use(router)
.mount('#app');

router.afterEach((to, from, failure) => {
  if (!failure) {
    nextTick(() => {
      app.config.globalProperties.$posthog.capture('$pageview', { path: to.fullPath });
    });
  }
});

Vue 2.x:

JavaScript

export default new Router({
    /*
     *
   *
   */
  afterEach: to => {
    nextTick(() => {
      posthog.capture("$pageview", {
        $current_url: to.fullPath
      });
    });
  }
});

Capturing pageleaves

Similar to pageviews, you need to manually capture pageleaves in a Vue single-page app.

This starts by setting capture_pageleave to false in the PostHog initialization config to ensure you don’t double-capture pageleaves.

JavaScript

// In the file where you initialize PostHog
posthog.init(
      "<ph_project_api_key>",
      {
        api_host: "https://us.i.posthog.com",
        person_profiles: 'identified_only',
        capture_pageview: false,
        capture_pageleave: false
      }
);

Vue 3.x:

You can then use the same router.afterEach hook to capture pageleaves. The difference is that you need to manually set the $current_url and path properties using the from object.

JavaScript

import { createApp, nextTick } from 'vue'
import App from './App.vue'
import router from './router'
import posthogPlugin from '../plugins/posthog';


const app = createApp(App);
app.use(posthogPlugin)
.use(router)
.mount('#app');

router.afterEach((to, from, failure) => {
  if (!failure) {
    nextTick(() => {
      app.config.globalProperties.$posthog.capture('$pageleave', { $current_url: window.location.host + from.fullPath, path: from.fullPath });
      app.config.globalProperties.$posthog.capture('$pageview', { path: to.fullPath });
    });
  }
});

Capturing events

Here’s a simple example of using PostHog to capture a barebones login button.

JavaScript

//component.vue

<script>
export default {
  data(props) {
    return {
      user: props.user,
    };
  },
  created() {
    console.log("Created", this.$posthog); //posthog accessible anywhere!
  },
    methods: {
        login() {
            this.$posthog.capture("User logged in"); 
            //should be this.posthog if you used method 2! 
        }
    }
};
</script>
<template>
    <button @click="login">Login!</button>
</template>

You can the access the project used in this tutorial on GitHub.

Next steps

For any technical questions for how to integrate specific PostHog features into Vue (such as analytics, 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:

Prerequisites

Setting up PostHog

Initializing PostHog

Method 1: Create a Plugin

Method 2: Use provide / inject

Step 1: Initialize Vue

Step 2: Inject into any Vue file

Method 3: Use Vue.prototype

Method 4: Use the Composition API

Capturing pageviews

Capturing pageleaves

Capturing events

Next steps

Questions?

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