A few tips in order

• restart the terminal
• restart the machine
• reinstall nodejs + then run npm install typescript -g

If it still doesn't work run npm config get prefix to see where npm install -g is putting files (append bin to the output) and make sure that they are in the path (the node js setup does this. Maybe you forgot to tick that option).

It took me a while to figure out the solution to this problem - it's in the original question. You need to have a script that calls tsc in your package.json file so that you can run:

npm run tsc 

Include -- before you pass in options (or just include them in the script):

npm run tsc -- -v

Here's an example package.json:

{
  "name": "foo",
  "scripts": {
    "tsc": "tsc"
  },
  "dependencies": {
    "typescript": "^1.8.10"
  }
}