How to Fix Facebook SDK with Nuxt.js

Are you struggling to integrate Facebook SDK into your Nuxt.js project and encountering the dreaded window.FB is undefined error? You’re not alone! This common issue arises due to Nuxt.js’s server-side rendering (SSR) setup, which doesn’t recognize browser-specific objects like window during the initial server render. Let’s break down the problem and explore a robust solution.

Why Does the Error Occur

Nuxt.js pre-renders pages on the server, where browser APIs such as window or document don’t exist. If your code tries to access window.FB during this phase, it throws an error. In your current setup:

• The Facebook SDK script (fb-sdk.js) is loaded globally via nuxt.config.js, which runs on both server and client.
• The SDK initialization relies on window, which is undefined during SSR.

Here’s how to resolve the issue and properly integrate Facebook SDK into Nuxt.js:

Create a Client-Side Plugin

Nuxt plugins can be configured to run only on the client, avoiding SSR conflicts. Let’s create a plugin for initializing Facebook SDK.

Create plugins/facebook-sdk.js:

export default function ({ app }) {
  // Run only on client-side
  if (process.client) {
    window.fbAsyncInit = function() {
      FB.init({
        appId: '############', // Replace with your app ID
        cookie: true,
        xfbml: true,
        version: 'v9.0'
      });
      FB.AppEvents.logPageView();
    };

    // Load SDK script dynamically
    (function(d, s, id) {
      var js, fjs = d.getElementsByTagName(s)[0];
      if (d.getElementById(id)) return;
      js = d.createElement(s);
      js.id = id;
      js.src = "https://connect.facebook.net/en_US/sdk.js";
      fjs.parentNode.insertBefore(js, fjs);
    })(document, 'script', 'facebook-jssdk');
  }
}

Register the Plugin in nuxt.config.js

Update your Nuxt config to load the plugin client-side only:

export default {
  plugins: [
    { src: '~/plugins/facebook-sdk.js', mode: 'client' }
  ],
  head: {
    // Remove the script tag for fb-sdk.js here
  }
}

Accessing window.FB Safely

Even after initializing the SDK, ensure window.FB is available before using it. In your Vue component:

export default {
  methods: {
    fbLog() {
      if (process.client && window.FB) {
        window.FB.getLoginStatus((response) => {
          this.statusChangeCallback(response);
        });
      } else {
        console.error('Facebook SDK not loaded');
      }
    },
    statusChangeCallback(response) {
      console.log(response);
    }
  },
  mounted() {
    // Optional: Delay execution if SDK takes time to load
    setTimeout(() => this.fbLog(), 1000);
  }
}

Use Nuxt Community Modules

For a more streamlined approach, consider using community-maintained Nuxt modules like @nuxtjs/facebook. These handle client-side initialization automatically.

Final Thoughts

Integrating third-party scripts like Facebook SDK into Nuxt.js requires careful handling of SSR limitations. By isolating client-side logic in plugins and guarding against undefined objects, you ensure compatibility with Nuxt’s architecture. Remember:

• Always check for process.client when using browser APIs.
• Load scripts dynamically to avoid blocking page rendering.
• Use community modules where possible to reduce boilerplate.

With this setup, you’ll have a working Facebook SDK integration in Nuxt.js without window.FB errors.