env-config-map

Generates a config object from a config map using any input sources. Mapping includes the most commonly encountered patterns such as setting default value, type casting, coercing null, coercing undefined, and redacting secrets for logging. Default input source are environment variables from process.env.

• Zero dependency.
• Supported types:
  • string
  • number
  • boolean
  • object
  • arrayCommaDelim
  • also supports custom types
• redact option to redact value for logging.
• coerceNull option to coerce "null" to null.
• coerceUndefined option to coerce "undefined" to undefined.
• getter option to get input values from other sources. Default source is process.env.

Installation

npm install env-config-map

Run Sandbox Example

npm run sandbox

Sandbox Example

// source from .env (optional)
// require('dotenv').config();
 
const envConfigMap = require('env-config-map');
 
// setup fixture data for example
process.env.SERVER_HOST = '0.0.0.0';
process.env.SERVER_PORT = 8080;
process.env.MAINTENANCE_MODE = 'true';
process.env.ENABLE_PROFILER = 'NO';
process.env.SETTINGS = '{ "path": "/tmp", "timeout": 1000 } ';
process.env.ACCESS_KEY = 'myAccessKey';
process.env.COERCE_NULL_DEFAULT = 'null';
process.env.COERCE_NULL_DISABLED = 'null';
// process.env.LOG_LEVEL = undefined;
 
const configMap = {
  SERVER_HOST: { default: 'localhost' },
  SERVER_PORT: { default: 80, type: 'number' },
  MAINTENANCE_MODE: { default: false, type: 'boolean' },
  ENABLE_PROFILER: { default: false, type: 'booleanYesNo' },
  SETTINGS: { type: 'object' },
  ACCESS_KEY: { redact: true },
  COERCE_NULL_DEFAULT: {},
  COERCE_NULL_DISABLED: { coerceNull: false },
  LOG_LEVEL: { default: 'info' },
};
 
const options = {
  types: {
    // define custom type "booleanYesNo"
    booleanYesNo: (str) => {
      const normalized = envConfigMap.utils.lowerTrim(str);
      if (normalized === 'yes') return true;
      if (normalized === 'no') return false;
      return null;
    },
  },
  // customize redactor
  redactor: (str) => str.replace(/.+/, '*** REDACTED ***'),
};
 
const config = envConfigMap(configMap, options);
 
console.log(config);
console.log(config.getRedacted());

console.log(config);

{
  SERVER_HOST: '0.0.0.0',
  SERVER_PORT: 8080,
  MAINTENANCE_MODE: true,
  ENABLE_PROFILER: false,
  SETTINGS: { path: '/tmp', timeout: 1000 },
  ACCESS_KEY: 'myAccessKey',
  COERCE_NULL_DEFAULT: null,
  COERCE_NULL_DISABLED: 'null',
  LOG_LEVEL: 'info',
  getRedacted: [Function],
  getOptions: [Function]
}

console.log(config.getRedacted());

{
  SERVER_HOST: '0.0.0.0',
  SERVER_PORT: 8080,
  MAINTENANCE_MODE: true,
  ENABLE_PROFILER: false,
  SETTINGS: { path: '/tmp', timeout: 1000 },
  ACCESS_KEY: '*** REDACTED ***',
  COERCE_NULL_DEFAULT: null,
  COERCE_NULL_DISABLED: 'null',
  LOG_LEVEL: 'info'
}

configMap

• default : mixed
  • Sets the default value.
• type : string (default: string)
  • Specify the type for the key. Cast operation will call the type casting function defined in options.types.
    • string
    • number
    • boolean
    • object
    • arrayCommaDelim
• redact : boolean
  • Flag to indicate if the value is a secret and needs to be redacted.
• coerceNull : boolean
  • Coerce string 'null' to null. Supersedes options.coerceNull.
• coerceUndefined : boolean
  • Coerce string 'undefined' to undefined. Supersedes options.coerceNull.

const configMap = {
  SERVER_PORT: { default: 80, type: 'number' },
  ACCESS_KEY: { redact: true },
  ENABLE_PROFILER: { default: false, type: 'booleanYesNo' },
  COERCE_DISABLED: { coerceNull: false, coerceUndefined: false },
};
const config = envConfigMap(configMap, options);

options

• getter : function
  • Get input value for key. Default source is process.env.
• types : object
  • For defining additional types and it will merge with the supported types.
• redactor : function
  • Function to redact value flaged with the redact configMap option.
• coerceNull : boolean (default: true)
  • Coerce string 'null' to null.
• coerceUndefined : boolean (default: true)
  • Coerce string 'undefined' to undefined.

const options = {
  getter: (key) => process.env[key],
  types: {
    // define custom type "booleanYesNo"
    booleanYesNo: (str) => {
      const normalized = envConfigMap.utils.lowerTrim(str);
      if (normalized === 'yes') return true;
      if (normalized === 'no') return false;
      return null;
    },
  },
  // customized redactor
  redactor: (str) => str.replace(/.+/, '*** REDACTED ***'),
  coerceNull: true,
  coerceUndefined: false,
};
const config = envConfigMap(configMap, options);

Misc Exports

const envConfigMap = require('env-config-map');
const defaultOptions = envConfigMap.defaultOptions;
const supportedTypes = envConfigMap.types;
const helperUtils = envConfigMap.utils;

Example Server Config with env-config-map

.env

APP_NAME = envConfigMap;
SERVER_PORT = 8080;
ACCESS_KEY = myAccessKey;

config.js

require('dotenv').config();
const envConfigMap = require('env-config-map');
 
const configMap = {
  APP_NAME: { default: 'noname' },
  SERVER_HOST: { default: 'localhost' },
  SERVER_PORT: { default: 80, type: 'number' },
  ACCESS_KEY: { redact: true },
};
const config = envConfigMap(configMap);
 
module.exports = config;

server.js

const http = require('http');
const config = require('./config.js');
 
console.log('Configs loaded.', config.getRedacted());
 
http
  .createServer((req, res) => {
    res.write(`Hello ${config.APP_NAME}!`);
    res.end();
  })
  .listen(config.SERVER_PORT, config.SERVER_HOST, () => console.log(
    `server listening on ${config.SERVER_HOST}:${config.SERVER_PORT}`,
  ));

License

Copyright © 2019 Joe Yu. Licensed under the MIT License.