After Vue build, get an unexpected token error ‘??’ in web browser

Built a Vue application in Visual Studio using Typescript. Ran the build command for production to get the compiled Javascript file. When I run the script in a browser, I get a syntax error for an unexpected token ‘??’. The ‘??’ only appears in the output file and not in the Typescript code. The nullish coalescing operator is valid Javascript.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing

example from the Vue generated Javascript file

(n ?? (n = e.get(i) === i._trackId))

I’m at a loss as to how to fix this. Suggestions?