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Configuration

Applications often need to be configured to run in different environments. For example, you might want to use a different database in development than in production.

Thanks to dotenv, KoalaTs provides a practical way to manage application configuration.

Environment files​

A fresh KoalaTs application contains a .env file in the root of your project. This file contains the default values needed to run your application. It also comes with a .env.test file that contains the default values for your tests.

Accessing configuration values​

You can access configuration values using the process.env object. For example, to access the PORT value, you can use the following code:

const port = process.env.PORT;

Overriding configuration values​

If you need to override an environment value, you can do that in a .env.local file:

DATABASE_URL="mysql://root:@127.0.0.1:3306/my_database_name"
caution

The .env.local file should not be committed to your repository. It is meant to be used for local development only.

Several other .env files are available to set environment variables in the right situation:

  • .env: defines the default values of the env vars needed by the application
  • .env.local: overrides the default values for all environments but only on the machine which contains the file
  • .env.<environment> such as .env.test: overrides env vars only for one environment but for all machines
  • .env.<environment>.local such as .env.test.local: defines machine-specific env var overrides only for one environment

Selecting the environment​

The environment is selected by the NODE_ENV environment variable. If you do not set it, the default value is development. You can set it before running your application:

NODE_ENV=production npm start

Or in your package.json scripts:

{
  "scripts": {
    "start": "NODE_ENV=production node dist/index.js"
  }
}