Over a year ago I create a cross site collection navigation solution aka global navigation for Modern SharePoint sites using all the Microsoft goodies like SPFx, PowerShell PnP, PnP-JS & Office UI Fabric. At the same time, I had a very similar solution for Classic SharePoint sites for a different batch of clients. It was fairly typical for clients new to Office 365 go straight Modern and some of the more traditional SharePoint clients to stick with Classic sites.
How can an SPFx Application Customizer work on Classic sites?
For Modern sites when you create a web part or app customizer there is a top level file. For example: in the global navigation project – SpfxGlobalNavigationApplicationCustomizer.ts. This file registers the Application Customizer and then loads the GlobalNav component into the Header placeholder [available on all Modern pages]. Everything inside the GlobalNav.tsx is React and nothing special.
For Classic sites there is no built-in framework to inject components. This is something that must be addressed. In the global navigation project I create a component called ClassicMode.ts which is the top level file.
Inside that file there is a reference to include @bable/polyfill. That helps supplement any browser shortcomings. On a Modern site there are already some polyfills so this would be unnecessary.
Next there is a secondary style sheet which would be used to handle style differences between Classic & Modern sites. In the global navigation project, I am reference the Office UI Fabric library for icons. On a Modern site those are also already there so this would be unnecessary.
Finally, on window load, the GlobalNav component is created into the element #DeltaTopNavigation. The DeltaTopNavgiation is the element where the default navigation is on a Classic SharePoint site.
** For this navigation scenario I am overwriting the default out of the box navigation. You can create a new DOM element and inject that anywhere and mount your React component into that new element. **
That’s it in terms of the code. The code of the GlobalNav component is the same for both Modern & Classic sites. The Modern Application Customizer points to the same files that the ClassicMode component points to.
Building an SPFx Application Customizer for Classic Sites
In the SPFx Application Customizer folder create a webpack.config.js. This will tell webpack to use our ClassicModer.ts as the entry point and produce a new file called top-navigation.js in a folder called classic-dist
To execute webpack against this new file just run the following command:
npx webpack --config webpack.config.js
Note: This webpack file uses a few new dependencies that are NOT included with an SPFx project. You must include these new dependencies before you attempt to run webpack against this new config file.
Attaching Classic Mode build to SharePoint Site
The last thing we need to cover is how to hook up this file into your Classic SharePoint site. It’s straight forward and if you made it this far it should be a piece of cake.
Step 1 – Upload the file. You can manually copy / paste the file into SharePoint. Alternatively you could host this file on a CDN if the plan is to use it on more than 1 site collection.
Alternatively, check out how I upload it and activate it using PowerShell PnP with a deploy script.
That wraps up how to use your SPFx Application Customizer on a Classic SharePoint site. The most complicated part for me was building out the webpack.config.js file. It was a little tricky finding the right polyfills, getting the loading to work and testing across versions of SharePoint. I have even used this approach, for this project SPFx Global Navigation Application Customizer, on a SharePoint 2013 site. Interested in that solution check out my other article Cross Site Collection Navigation for Modern & Classic SharePoint Sites. Enjoy!