flex_conf

Flexible configuration file management.

Based on the nconf package, the flex_conf package provides tag-based, hierarchical configuration file loading with atomic object merging. It is possible to register one or more "tags" e.g., env for environment-specific configuration files. These tags can then be used inside the configuration file's filename and/ or in folder names to conditionally load the configuration file.

Installation

Installation is straight forward with npm:

npm install flex_conf

Example

A minimal config module using flex_conf looks like this:

# config.js
const FlexConf = require('flex_conf');

const conf = new FlexConf('configs', {
  tagDefinitions: {
    env: {
      applies: value => process.env.NODE_ENV === value,
      map: (value) => {
        switch (value) {
          case 'dev': return 'development';
          case 'prod': return 'production';
          case 'test': return 'test';
          default: throw Error(`Unknown NODE_ENV in configfile name: '${value}'`);
        }
      },
    },
  },
});

module.exports = conf.final();

We can now create various configuration files inside the configs/ directory that will be parsed based on the value of the NODE_ENV environment variable:

configs/
├── database.env-dev.json
├── database.env-prod.json
└── database.json

For example, NODE_ENV=development would result in the database.env-dev.json file being loaded first, followed by the database.json as it is unconditionally loaded in any case (as no tags are specified).

To access the final configuration object in another module, we simply require the config module:

# example.js
const config = require('./config');

function connect() {
  console.log(`Connection to database '${config.database.username}@${config.database.host}:${config.database.port}'`);
}

connect();

Note: This example is also included in the GitHub repository under example/.

API Documentation

The API documentation can be found here: https://decentro-gmbh.github.io/flex_conf/