How to access and cast environment variables#
The env() utility accesses environment variables from .env files and casts them to different types including int, float, bool, json, array, date, and oneOf.
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')