getting nyc/istanbul coverage report to work with typescript

Recently I found a satisfiable solution by using "target": "es6" instead of es5 in tsconfig.json's compilerOptions. While changing target directly in tsconfig.json may not be an option as it affects build, the other tip is to use TS_NODE_COMPILER_OPTIONS='{"target":"es6"} which can be added directly in package.json scripts as i.e. :

"test:coverage": "TS_NODE_COMPILER_OPTIONS='{\"target\":\"es6\"}' nyc npm run test:unit",

where test:unit is whatever way being used to run actual tests (in my case just gulp mocha.

NOTE: I've also updated nyc to latest 11.1.0 and ts-node to 3.3.0 as suggested on https://github.com/istanbuljs/nyc/issues/618 thread

I'm not sure this is the same problem but I'll put this here in case it helps future developers...

I wasn't getting any coverage data until I added exclude-after-remap=false to the nyc section of my package.json.

This is listed in the documentation but not in a very prominent way (IMO).