dotenv-handler
v1.3.0
Published
A lightweight helper for loading, setting, and saving environment variables using dotenv.
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dotenv-handler
dotenv-handler
is a lightweight utility for managing environment variables in your Node.js applications. It provides an easy way to load, access, and manage environment variables with additional features like default values and required checks.
Installation
npm install dotenv-handler
or
pnpm add dotenv-handler
Usage
Load environment variables
import { loadConfig, getConfig } from 'dotenv-handler';
// Load configuration from .env file
loadConfig('.env', {
// Set default values for environment variables
defaults: {
DEFAULT_KEY: 'defaultValue',
// Expand must be set to true to use environment variables in default values
DATABASE_URL: 'localhost:${PORT}/${DB_NAME}',
},
// Validate required environment variables
required: ['PORT', 'DB_USER', 'DB_NAME'],
// This will allow environment variables to be expanded
expand: true,
// Apply transformations to environment variables
transformations: {
PORT: value => parseInt(value, 10).toString(),
DEFAULT_KEY: value => value.toUpperCase(),
},
});
// Get configuration values
const port = getConfig('PORT');
const dbUser = getConfig('DB_USER');
const dbUrl = getConfig('DATABASE_URL');
console.log(`Server will run on port: ${port}`);
console.log(`Database user: ${dbUser}`);
console.log(`Database URL: ${dbUrl}`);
Set default values for environment variables
loadConfig('.env', {
defaults: {
DEFAULT_KEY: 'defaultValue',
},
});
Validate required environment variables
loadConfig('.env', {
required: ['PORT', 'DB_USER'],
});
Save environment variables to a file
import { setEnv, saveConfig } from 'dotenv-handler';
setEnv('NEW_KEY', 'newValue');
saveConfig('.env');
Expanding environment variables
loadConfig('.env', {
defaults: {
DB_HOST: 'localhost',
DB_PORT: '5432',
DATABASE_URL: '${DB_HOST}:${DB_PORT}/database',
},
// This will allow environment variables to be expanded
expand: true,
required: ['DATABASE_URL'],
});
const databaseUrl = getConfig('DATABASE_URL');
console.log(`Database URL: ${databaseUrl}`);
Apply custom validation logic
import { loadConfig, getConfig } from 'dotenv-handler';
import Joi from 'joi';
const schema = Joi.object({
PORT: Joi.number().port().required(),
DB_USER: Joi.string().required(),
DB_NAME: Joi.string().required(),
});
loadConfig('.env', {
required: ['PORT', 'DB_USER', 'DB_NAME'],
validate: config => {
const { error, value } = schema.validate(config);
if (error) {
throw new Error(`Invalid configuration: ${error.message}`);
}
return value;
},
});
const port = getConfig('PORT');
const dbUser = getConfig('DB_USER');
const dbName = getConfig('DB_NAME');
console.log(`Server will run on port: ${port}`);
console.log(`Database user: ${dbUser}`);
console.log(`Database name: ${dbName}`);
Apply transformations to environment variables
loadConfig('.env', {
// Apply transformations to environment variables
transformations: {
PORT: value => parseInt(value, 10).toString(),
DB_USER: value => value.toUpperCase(),
},
});
const port = getConfig('PORT');
const dbUser = getConfig('DB_USER');
console.log(`Server will run on port: ${port}`);
console.log(`Database user: ${dbUser}`);
Silence errors on missing required variables
loadConfig('.env', {
required: ['PORT'],
errorOnMissing: false,
});
Basic usage with CommonJS
const { loadConfig, getConfig } = require('dotenv-handler');
loadConfig('.env');
const port = getConfig('PORT');
console.log(`Server will run on port: ${port}`);
Use dotenv config object
import { loadConfig } from 'dotenv-handler';
loadConfig({ path: '.env.test' }, { required: ['PORT', 'DB_USER'] });
const port = getConfig('PORT');
const dbUser = getConfig('DB_USER');
console.log(`Server will run on port: ${port}`);
console.log(`Database user: ${dbUser}`);
API
loadConfig(envFilePathOrOptions: string | DotenvConfigOptions, options?: LoadConfigOptions): void
Loads environment variables from the specified file.
envFilePathOrOptions
: Path to the file where environment variables are stored or a dotEnv config object.options
: An object with the following properties:defaults
: An object with default values for environment variables.required
: An array of environment variables that are required.expand
: A boolean value indicating whether to expand environment variables.errorOnMissing
: A boolean value indicating whether to throw an error if a required environment variable is missing.transformations
: An object with transformation functions for environment variables.validate
: A function that applies custom validation logic to the loaded configuration.
getConfig(key: string): string | undefined
Returns the value of the specified environment variable.
key
: The name of the environment variable.
setEnv(key: string, value: string): void
Sets the value of the specified environment variable.
key
: Thevalue
: The value to set.
saveConfig(path: string): void
Saves the current environment variables to the specified file.
path
: Path to the file where environment variables should be saved.