In apps with different Roles and permissions you may need to get information about AD Groups. Here are some snippets which can help you with this part of the task.

While the development SPFX for SharePoint 2019 once the loading of the webpart at 'workbench.aspx' page stopped. SharePoint server is installed at my virtual machine, the development of SPFX is local. At first I totally could not understand what's wrong. But soon started to look for the reason.

When you make a SharePoint 2019 on-premises solution, you can make not only SPFX solutions, but also old-school WSP-solutions. It allows you not only to use SharePoint API, but also to use your own API services. With SharePoint 2019 you can use WCF service. For example, it’s a good way when you develop an application which uses the external database. This works also for SharePoint 2013 and SharePoint 2016.

If you want to get the Author login from the SharePoint object, for example, list item, you should use 'expand=Author' in the query. It's necessary, but not sufficient. There's one more option, which you must use.

I developed a service for SharePoint 2019 (on premise) and this service should move files from document library to an external storage. The client part is made with SPFX solution – command set. It added buttons to the interface of the document library.

When I started to work with SPFX solutions for SharePoint, I couldn’t understand how to load external CSS files. I came up with one solution, but it was a crutch. I did it with embedding <styles> tag into JSX. It looked like this:

While writing the script to create lists for my solution for SharePoint Online I had to rename Title field in a list. It's not so obviously as just to create a new field.

I used EventCalendar component with resources and timeline view, the default interval is 1 month, I also add week numbers to the header. I wanted to fit the calendar to the page without horizontal scroll.

The queries to get all the list items, get list items with specific field values, get list items by ContentType Name. The most of the time I spend with the last one.

Many times I told myself not to work with SharePoint, but it's forever with me 🙂
My colleague asked to help him with a problem with modern lists. There some simple fields, without lookups. But there's an error in displaying items. I spent about an hour to determine the problem - created a copy of the list, removed all items, added items with only 1 filled field. It worked in classic view, but not in modern.