Q:

Getting 'cannot redeclare block-scoped variable' for 'message' variable

I'm an desktop application developer trying to learn the avalanche of technologies for web programming. I decided to focus with Angular(2-4 whatever) because it seemed like the it might be around for more than a year. I'm taking a course that is focusing on TypeScript right now. I'm using Visual Studio Code (1.14.0 - I just updated it) with TypeScript version 2.4.1 (That's what it shows in the lower right corner).
The instructor is showing us how to 'transpile' with command lines (which was another mess I wasted my morning on - see tsc.cmd as opposed to tsc).
The example in question is simply this one line, the first and only line in the Visual Studio Code editor:
let message = 0;

I get the red line of error under the 'message' telling me that:

[ts] Cannot redeclare block-scoped variable 'message'.

It worked for the instructor (on his MAC) but so did the ts compiler command.
If I change it to 
let messag = 0;

The error goes away. I can't find where message is a command, statement or global variable in Type Script. 
It seems like I'm running the latest of node and type script. I just worry that something is not correctly installed on my machine.

A:

I am still getting use to the idiosyncrasies of VS Code. 
My issue was that I put 'archive' copies of my previous code in a subfolder not realizing that these would be loaded as part of the 'assembly'.
Don't simply close the folder! If you are looking at just a single file, the editor will turn off intellisense for typescript.
My solution was to move my archived files out from under the folder AND rename them so their extension was no longer .ts.

