Production env on app deployed in heroku

Hello everyone,

I followed this tutorial and successfully deployed my app to heroku. The problem is it is not following the environments set on my .env.prod file. It is still using environments set on .env. The app is built using vue-cli 3.

My package.json has the following code. And already set NODE_ENV on heroku to production.

      "scripts": {
        "build": "vue-cli-service build --mode production",
        "dev": "vue-cli-service serve --open",
        "start": "node server.js"
      }           

anything I am missing here?

solve this issue by run build --mode prod