No success modifying CameraView class to test for latitude/longitude

I have been trying to modify ./terriajs/lib/Models/CameraView.ts
to include new logic into the constructor of the CameraView class, to return before initiating the rectangle member, in certain conditions.
As a test, I changed the code to do a return before initiating the rectangle member in all situations. I was expecting this to break the UI but is hasn’t, which doesn’t seem right to me.
Note, I also changed ./terriajs/dist/Models/CameraView.js
by compiling the .ts into .js using tsc CameraView.ts

I am a newbie with this development environment, so I am probably doing a dumb newbie mistake.

Appreciate any help you can give. THX.