strict-env-conf

NPM package for easy work with ENV-based configuration

Usage

Just two examles...

The first idea: if something wrong with your environment variables - your application must crashes on startup, not in arbitrary time when running.

const sec = require('strict-env-conf');

const tpl = {
  scopes: {
    DB: [
      {name: "PASSWORD"}
    ]
  }
};

sec(tpl);

Output:

...
Error: Required env variable DB_PASSWORD is not set
...

The second idea - parsing string values from environment variables to convenient JS-object with several types of properties.

const sec = require('strict-env-conf');
const filters = require('strict-env-conf/src/filters');

const envVars = {
  SEC_APP_HOST:                   'example.com',
  SEC_APP_PORT:                   '80',
  SEC_DB_EXTERNAL_AUTH:           'true',
  SEC_DB_PORT:                    '444',
  SEC_LDAP_TEST_USER_EMAIL:       'null',
  SEC_LDAP_TEST_USER_ID:          '4321',
};

for (let varName in envVars) {
  process.env[varName] = envVars[varName];
}

const template = {
  prefix: 'SEC_', // env variables app-level prefix for safety
  // filters: [str => String(str).trim()] <-- this is by default. Set "filters: []" to avoid this behavior.
  scopes: {
    APP: [
      {name: "HOST", default: "localhost"},
      {name: "PORT", default: 3000} // "filters: [Number]" is redundant here, Number is default filter if (typeof default === 'number')
    ],
    DB: [
      {name: "EXTERNAL_AUTH", default: false}, // default filter for boolean types works with "0", "1", "true", "false"
      {name: "PORT", filters: [Number]}, // no default value here, just the Number filter - the variable is required 
      {name: "NAME", default: "my-app"}
    ],
    LDAP: [
      {name: "TEST_USER_LOGIN", default: undefined}, // if default === undefined - you must check in your application code what conf object have this property
      {name: "TEST_USER_EMAIL", default: undefined, filters: [filters.maybeNull]},
      {name: "TEST_USER_ID", default: undefined, filters: [Number]},
    ],
    DATA: [
      {name: "CATEGORIES", default: "2,1,E", filters: [filters.csv2array]}, // you also can use your own filters. Filter function example: stringValue => 'MY_' + stringValue 
    ],
  }
};

const testConf = sec(template);
console.log(JSON.stringify(testConf, null, '    '));

Output:

{
    "app": {
        "host": "example.com",
        "port": 80
    },
    "db": {
        "external_auth": true,
        "port": 444,
        "name": "my-app"
    },
    "ldap": {
        "test_user_email": null,
        "test_user_id": 4321
    },
    "data": {
        "categories": [
            "2",
            "1",
            "E"
        ]
    }
}

Installation

npm i strict-env-conf

License

MIT