Why is tsc called twice in this npm start script?

The package.json example at this link includes the following start commands:

"start": "tsc && concurrently \"npm run tsc:w\" \"npm run lite\" ",  

What explicitly does the above command do?

I think that the "concurrently \"npm run tsc:w\" \"npm run lite\" " means to start both tsc and lite-server simultaneously, and to also place a watch on the tsc so that changes are reloaded into lite-server immediately. Is this correct? And also, why call tsc twice? What is an explicit explanation of the entire line of code including all of its constituent parts put together?

via CodeMed