Using 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 provided by Quasar CLI
| process∙env∙<name> | Type | Meaning | 
|---|---|---|
| DEV | Boolean | Code runs in development mode | 
| PROD | Boolean | Code runs in production mode | 
| DEBUGGING | Boolean | Code runs in development mode or --debugflag was set for production mode | 
| CLIENT | Boolean | Code runs on client (not on server) | 
| SERVER | Boolean | Code runs on server (not on client) | 
| MODE | String | Quasar CLI mode ( spa,pwa, …) | 
| NODE_ENV | String | Has two possible values: productionordevelopment | 
| TARGET | String | Can be iosorandroidfor Cordova/Capacitor modes andchromeorfirefoxfor BEX mode | 
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') {
  import('@electron/remote').then(({ BrowserWindow }) => {
    const win = 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, 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
You can add your own definitions to process.env through the /quasar.config file.
It’s important to understand the different types of environment variables.
- The env variables from the terminal that are defined in the /quasar.configfile
- The environment variables that you pass to your UI code
// Accessing terminal variables
console.log(process.env)
export default defineConfig((ctx) => {
  return {
    // ...
    build: {
      // passing down to UI code from the quasar.config file
      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 will point to one of those two links above, depending on dev or production build type.
You can even combine it with values 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 the /quasar.config file
build: {
  env: {
    API: ctx.dev
      ? 'https://dev.' + process.env.MY_API
      : 'https://prod.' + process.env.MY_API
  }
}The env dotfiles support
Expanding a bit on the env dotfiles support. These files will be detected and used (the order matters):
.env                                # loaded in all cases
.env.local                          # loaded in all cases, ignored by git
.env.[dev|prod]                     # loaded for dev or prod only
.env.local.[dev|prod]               # loaded for dev or prod only, ignored by git
.env.[quasarMode]                   # loaded for specific Quasar CLI mode only
.env.local.[quasarMode]             # loaded for specific Quasar CLI mode only, ignored by git
.env.[dev|prod].[quasarMode]        # loaded for specific Quasar CLI mode and dev|prod only
.env.local.[dev|prod].[quasarMode]  # loaded for specific Quasar CLI mode and dev|prod only, ignored by git…where “ignored by git” assumes a default project folder created after releasing this package, otherwise add .env.local* to your /.gitignore file.
You can also configure the files above to be picked up from a different folder or even add more files to the list:
build: {
  /**
   * Folder where Quasar CLI should look for .env* files.
   * Can be an absolute path or a relative path to project root directory.
   *
   * @default project root directory
   */
  envFolder?: string;
  /**
   * Additional .env* files to be loaded.
   * Each entry can be an absolute path or a relative path to quasar.config > build > envFolder.
   *
   * @example ['.env.somefile', '../.env.someotherfile']
   */
  envFiles?: string[];
  /**
   * Filter the env variables that are exposed to the client
   * through the env files. This does not account also for the definitions
   * assigned directly to quasar.config > build > env prop.
   *
   * Requires @quasar/app-vite v2.0.3+
   */
  envFilter?:
    (env: { [index: string]: string | boolean | undefined | null })
      => { [index: string]: string | boolean | undefined | null };
}Remember that you can filter out unwanted keys, or even change values for keys by using build > envFilter:
build: {
  // @quasar/app-vite v2.0.3+
  envFilter (originalEnv) {
    const newEnv = {}
    for (const key in originalEnv) {
      if (/* ...decide if it goes in or not... */) {
        newEnv[ key ] = originalEnv[ key ]
      }
    }
    // remember to return your processed env
    return newEnv
  }
}Troubleshooting
You might be getting process is not defined errors in the browser console if you are accessing the variables wrong or if you have a misconfiguration.
Wrong usage
build: {
  env: {
    FOO: 'hello',
  }
}const { FOO } = process.env // ❌ It doesn't allow destructuring or similar
process.env.FOO             // ✅ It can only replace direct usage like this
function getEnv(name) {
  return process.env[name] // ❌ It can't analyze dynamic usage
}
console.log(process)     // ❌
console.log(process.env) // ❌
// If you want to see a list of available env variables,
// you can log the object you are passing to `build > env` inside the `quasar.config` file
console.log(process.env.FOO) // ✅
console.log(process.env.foo) // ❌ Case sensitive
console.log(process.env.F0O) // ❌ Typo in the variable name (middle o is 0(zero))Misconfiguration
Manual definition
build: {
  env: {
    FOO: 'hello',
  }
}console.log(process.env.FOO) // ✅
console.log(process.env.BAR) // ❌ It's not defined in `build > env`The env dotfiles
# order matters!
.env                                # loaded in all cases
.env.local                          # loaded in all cases, ignored by git
.env.[dev|prod]                     # loaded for dev or prod only
.env.local.[dev|prod]               # loaded for dev or prod only, ignored by git
.env.[quasarMode]                   # loaded for specific Quasar CLI mode only
.env.local.[quasarMode]             # loaded for specific Quasar CLI mode only, ignored by git
.env.[dev|prod].[quasarMode]        # loaded for specific Quasar CLI mode and dev|prod only
.env.local.[dev|prod].[quasarMode]  # loaded for specific Quasar CLI mode and dev|prod only, ignored by gitIf the /.env doesn’t exist or there is a typo in the file name:
console.log(process.env.FOO) // ❌ The .env file is not loaded, this will failIf the /.env file exists with the correct name, and has the following content:
FOO=helloconsole.log(process.env.FOO) // ✅ It's loaded correctly from the `.env` file
console.log(process.env.BAR) // ❌ It's not defined in the `.env` file