lazy-fb let's you load Facebook's JS SDK lazily.
It's just a very thin (~700 bytes) layer on top of Facebook's snippet.
Now, why would you want to do that? Well, you might only need the SDK in a few places of your app/site like your login or signup flow. So there's no need to load it in all the other places and force the user to download and evaluate all that JavaScript for nothing (~200kb).
Using npm:
$ npm install --save lazy-fb
Then with a module bundler like webpack, use as you would anything else:
// using ES modules
import lazyFB from 'lazy-fb'
// using CommonJS modules
const lazyFB = require('lazy-fb')The UMD build is also available on unpkg:
<script src="https://unpkg.com/lazy-fb/lazy-fb.min.js"></script>You can find the library on window.lazyFB.
The exported function returns a Promise which resolves with the SDK. So you can use it with promises or async/await. The SDK will also be globally available on window.FB. Calling the function multiple times will only load the SDK once.
const lazyFB = require('lazy-fb')
// Promises
lazyFB({ appId: 'your-app-id' }).then(FB => FB.getLoginStatus())
// async/await
const FB = await lazyFB({ appId: 'your-app-id' })
FB.getLoginStatus()On top of all the standard options for FB.init() like appId, xfbml, status, etc. you can pass the following options to change what will get loaded:
{
lang: 'en_US', // the language of the SDK
debug: false, // whether to load the debug build or not
sdkModule: '' // Facebook recently separated some modules from SDK. Other values are ['xfbml.customerchat']
}Take a look at https://developers.facebook.com/docs/javascript/advanced-setup for more options.