When I manually selected presets when installing vue using vue cli. I stumbled upon process.env.BASE_URL. I was tryng to find it in the internet but to no avail, I can't find any decent explanation. Here's the code.
const router = new VueRouter({
mode: 'history',
base: process.env.BASE_URL,
routes
})
the documentation is here https://cli.vuejs.org/guide/mode-and-env.html#environment-variables
It has a system of cascading files that will determine enviroment variables for your app. The main file being a .env
The BASE_URL is semi arbitary, you could introduce your own BASE_ROUTER_URL variable if you wanted
.env file in my project root. Where is it actually ?
vue create project_name. No .env file in the project root. Then how could it use process.env in the router as said in OP ?
BASE_URL is not arbitrary. (doc) BASE_URL - this corresponds to the publicPath option in vue.config.js and is the base path your app is deployed at.
.env file yourself. You should have different .env file for production .env and development: .env.development. You need to use the vue-cli-service serve --mode development to run your project in development mode.