Naboo's Podracing Misadventure

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    1.0.6 • Public • Published


    Load configuration through arguments, a .env file and environment variables in that order. Handling naming for you.

    By default, env-args will output logging information, and inform you if you're missing required arguments or environment variables.


    npm install --save @inlustra/env-args

    More in-depth

    An opinionated mechanism to load configuration from a given default configuration. By default, environment variables are prefixed with your package name (in package.json)

    Will automatically coerce both args and environment variables to their correct types:

    • --myVar='3000': would become {myVar: 3000}
    • --myVar='a full on string': would become {myVar: 'a full on string'}
    • --myVar=null: would become {myVar: null}
    • --myVar=undefined: would become {myVar: undefined}
    • --myVar='{test: 10}': would become {myVar: {test: 10}}
    • --myVar=user1 --myVar=user2: would become {myVar: ['user1', 'user2']
      • As an environment variable: MY_VAR=["user1", "user2"]


    Short Example

    Starting a project named exampleProject

    Providing the following configuration to the load method: {required: undefined}

    Running via npm (npm start) would require either an environment variable set as EXAMPLE_PROJECT_REQUIRED or the --required='my var' command line argument set.

    Running a node script (node index.js) would require either an environment variable set as REQUIRED or the --required='my var' command line argument set.

    All of this can be changed in using the provided configuration

    Full Example

    This example can be run by using npm i && npm start

    With package.json > name set to @inlustra/env-args


    const envArgs = require('@inlustra/env-args')
    const defaultConfiguration = {
      foo: 'A default string',
      notRequired: null,
      requiredNumber: undefined, // Passed in through .env file above
      alsoRequired: undefined, // Passed in through args below
      aNumber: undefined, // Passed in through args below
      overridden: 10 // Passed in through both, args, and .env file (Args takes preference)
    const loadedConfiguration = envArgs.load(defaultConfiguration, {
      envPrefix: 'ENV_ARGS'


    INLUSTRA_ENV_ARGS_OVERRIDDEN=This shouldnt appear

    Command Line

    node index.js --alsoRequired="Fixed" --aNumber="4000" --overriden=wooh!


    ------------ Start Environment Configuration ------------
        overridden: wooh!
        aNumber: 4000
        alsoRequired: Fixed
        requiredNumber: 92
        notRequired: null
        foo: A default string
    ------------ End Environment Configuration --------------
    { overridden: 'wooh!',
      aNumber: 4000,
      alsoRequired: 'Fixed',
      requiredNumber: 92,
      notRequired: null,
      foo: 'A default string' }

    Example output if arguments not supplied

    ------------ Environment configuration not set ------------
    Remember, you can override these by placing a .env file in your package.
    Argument --alsoRequired or environment variable ENV_ARGS_ALSO_REQUIRED
    Argument --aNumber or environment variable ENV_ARGS_A_NUMBER
            throw new EnvironmentNotSetError();
    Error: Missing environment configuration


    Key Type Description Defaults To
    arguments string[] The arguments to be parsed by minimist process.env.slice(2)
    envPrefix string Used to override the environment variable, example: required would become prefixrequired when overriden package name in constant format if run through npm, otherwise, empty.
    throwUndefined boolean Will enable/disable exceptions when there is missing config true
    logConfiguration boolean Will enable/disable the default logging once loaded true
    log (string) => any Used to override the default logger console.log
    envKeyTransform (string) => string Used to completely customise configuration key to environment variable mapping If package name exists, PACKAGE_NAME_FIELD, if it doesn't exist, but envPrefix is set: ENV_PREFIX_FIELD otherwise FIELD
    dotEnvPath string Passed to dotenv to specify the location of the .env file undefined (.env)
    dotEnvEncoding `'utf8' 'base64'` Passed to dotenv to specify the encoding of the variables in the dotenvfile

    Running tests

    npm i
    npm test


    npm i @inlustra/env-args

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