Accessing process.env can help you in many ways:

• differentiating runtime procedure depending on Quasar Mode (SPA/PWA/Cordova/Electron)
• differentiating runtime procedure depending if running a dev or production build
• adding flags to it based on terminal environment variables at build time

Values supplied by Quasar CLI

Example

if (process.env.DEV) {
  console.log(`I'm on a development build`)
}

// process.env.MODE is the <mode> in
// "quasar dev/build -m <mode>"
// (defaults to 'spa' if -m parameter is not specified)
if (process.env.MODE === 'electron') {
  const { remote } = require('electron')
  const win = remote.BrowserWindow.getFocusedWindow()

  if (win.isMaximized()) {
    win.unmaximize()
  }
  else {
    win.maximize()
  }
}

Stripping out code

When compiling your website/app, if () branches depending on process.env are evaluated and if the expression is false then they get stripped out of the file. Example:

if (process.env.DEV) {
  console.log('dev')
}
else {
  console.log('build')
}

// running with "quasar dev" will result in:
console.log('dev')
// while running with "quasar build" will result in:
console.log('build')

Notice above that the ifs are evaluated and also completely stripped out at compile-time, resulting in a smaller bundle.

Import based on process.env

You can combine what you learned in the section above with dynamic imports:

if (process.env.MODE === 'electron') {
  import('my-fancy-npm-package').then(package => {
    // notice "default" below, which is the prop with which
    // you can access what your npm imported package exports
    package.default.doSomething()
  })
}

Adding to process.env

@quasar/app v2 specs

You can add your own definitions to process.env through /quasar.conf.js file:

// quasar.conf.js

build: {
  env: {
    API: ctx.dev
      ? 'https://dev.api.com'
      : 'https://prod.api.com'
  }
}

Then in your website/app you can access process.env.API and it’s gonna point to one of those two links above, based on dev or production build type.

You can even go one step further. Supply it with values taken from the quasar dev/build env variables:

# we set an env variable in terminal
$ MY_API=api.com quasar build

# then we pick it up in /quasar.conf.js
build: {
  env: {
    API: ctx.dev
      ? 'https://dev.' + process.env.MY_API
      : 'https://prod.' + process.env.MY_API
  }
}