How to access and cast environment variables#

In most use cases there will be different configurations between environments (e.g. database credentials).

Instead of writing those credentials into configuration files, variables can be defined in a .env file at the root of the application:

# path: .env

DATABASE_PASSWORD=acme

To customize the path of the .env file to load, set an environment variable called ENV_PATH before starting the application:

ENV_PATH=/absolute/path/to/.env npm run start

Accessing environment variables#

Variables defined in the .env file are accessible using process.env.{variableName} anywhere in configuration and application files.

In configuration files, a env() utility allows defining defaults and casting values:


module.exports = ({ env }) => ({
  connections: {
    default: {
      settings: {
        password: env('DATABASE_PASSWORD'),
      },
    },
  },
});


export default ({ env }) => ({
  connections: {
    default: {
      settings: {
        password: env('DATABASE_PASSWORD'),
      },
    },
  },
});

Casting environment variables#

The env() utility can be used to cast environment variables to different types:

// Returns the env if defined without casting it
env('VAR', 'default');

// Cast to integer (using parseInt)
env.int('VAR', 0);

// Cast to float (using parseFloat)
env.float('VAR', 3.14);

// Cast to boolean (check if the value is equal to 'true')
env.bool('VAR', true);

// Cast to JS object (using JSON.parse)
env.json('VAR', { key: 'value' });

// Cast to array (syntax: ENV_VAR=[value1, value2, value3] | ENV_VAR=["value1", "value2", "value3"])
env.array('VAR', [1, 2, 3]);

// Cast to date (using new Date(value))
env.date('VAR', new Date());

// Returns the env matching oneOf union types
env.oneOf('UPLOAD_PROVIDER', ['local', 'aws'], 'local')