Angular CLI fileReplacements for default/development

I assume with "default/development configuration" you are referring to what is served with the ng serve command.

Option 1: replace environment files:

You can specify the fileReplacements array in the build object as well (this one is used for ng serve).

  "build": {
    "options": {
      [...]
      "fileReplacements": [
        {
          "replace": "src/environments/environment.ts",
          "with": "src/environments/environment.development.ts"
        }
      ]      
    },
    "configurations": {
      // other - non default - configurations 
    }
  }

Option 2: specifiy default configuration:

If you want to serve an already existing configuration withng serve, you can change the serve options:

  "configurations": {
    "youConfigName": {
      // config details here
    }
  },
  [...]
  "serve": {
    "options": {
      "browserTarget": "name-of-your-app:build:youConfigName"
    }
  }

The important point is to set the build configuration target with :yourConfigName.

---

Both options are configured per project and therefore allow you full control.