process.env.UV_THREADPOOL_SIZE not working?

On linux your code works fine:

UV_THREADPOOL_SIZE = 1;

fs: 20
Request: 108
Hash: 817
Hash: 1621
Hash: 2399
Hash: 3175

UV_THREADPOOL_SIZE = 5

fs: 11
Request: 120
Hash: 836
Hash: 857
Hash: 859
Hash: 871

If you're using windows, instead of setting it inside your javascript file, you have to set it before calling the script.

set UV_THREADPOOL_SIZE=1 & node app.js

The easiest solution for me was just to add a npm script entry like so:

{
  ...  
  "main": "app.js",
  "scripts": {
     "start": "set UV_THREADPOOL_SIZE=2 & node app.js"
  },
  ...
}

And then, in the cmd:

npm run start