Have fun trying to inspect Javascript code after it has gone through Webpack, Babel or anything else that may have been used for transpiling. Not saying it's impossible but it's still really annoying to do.
To add on to that, when there's an update, you usually can't diff it properly because large parts of the transpiled Javascript may change because of a one line change in the actual source code.
This is all assuming the website isn't actively trying to make it difficult for you to analyze their code.
At least if it's open source, you can inspect the source code then verify that the output is the same.