NYC mocha covering all files in my nodejs code except functions

Hello, I just run a test using NYC mocha on my nodejs repo, and I got a total coverage of 23.57%, config and models are 100% covered but controllers had only 19% covered, turned out it’s only covering the declaration of variables but not functions (i got coverage 0% for functions) Can anyone explain why ?

Here’s my package.json :

"scripts": {
    "start": "node server.js",
    "server": "nodemon server.js",
    "test": "nyc mocha --timeout 30000 ./controller/*.js --exit",
    "coverage": "./node_modules/.bin/nyc -r cobertura -r text-summary -r html npm test",
    "coverage-lcov": "./node_modules/.bin/nyc -r cobertura -r text-summary -r lcov npm test"
  },
  "devDependencies": {
    "chai": "4.2.0",
    "nodemon": "^2.0.4",
    "nyc": "^15.1.0",
    "mocha": "^8.1.3"
  },

Here’s an example of a function that’s not covered :

exports.getTickets = (req, res) => {
  Ticket.find().then(tickets => {
    res.status(200).send(tickets);
  });