nested-config

Configuration object wrapper for nested configs.

Features:

• Nested configs
• Deep merge of config objects
• Keeping track of defaults
• Plays nicely with nconf (see recipe below)
• See yargs-config to start yargs CLI application from the config

Usage

Create new config object using create(overrides [object], defaults [object]).

const nc = require('nested-config');
let config = nc.create({a: 'new value'}, {a: 'default value'});

Now config is itself a configuration object. All your current settings are stored in it. It keeps track of default options for you as well. The object has the following API.

config.a;  // 'new value'
config.getDefault('a');  // 'default value'

config.add({b: 1}, {b: 0});  // overrides, defaults
config.b;  // 1
config.getDefault('b');  // 0

Initialize with your default settings

const nc = require('nested-config');

let defaults = {
    yourOption: 1,
    nested: {
        option: "two",
        array: [1]
    }
};

let config = nc.create({yourOption: 2}, defaults);
config.yourOption;  // 2
config.nested.array; // [1] (default)

Update current settings

let overrides = {
    yourOption: 3,
    nested: {
        option: "three",
        array: [2]
    },
};

config.add(overrides, {});  // performs deep merge into current config state, leaves defaults unchanged
config.nested.array;  // [2]

Access settings

config.yourOption;  // 3
config.getDefault('yourOption');  // 1
config.nested.option;  // "three"
config.getPropRef('nested.option'); // "three" (same as above)
config.getDefault('nested.option');  // "two"

Additional options

By default, arrays are replaced. For concatenation, pass additional option {arrayBehavior: 1} to add. For more detail and other options, see API docs.

config.add({nested: {array: [3]}}, {}, { arrayBehavior: 1 });
config.nested.array;  // [2, 3]

Use nconf (if needed)

Prepare nconf wrapper:

const nconf = require('nconf');
const nc = require('./config');

let defaultConfig = nc.create({}, {some: "config"});

nconf
  .env()
  .argv()
  .defaults(defaultConfig);

// exports your current config
module.exports.nconf = nconf;  

// manipulate default config (e.g. add new options for embedded modules)
module.exports.defaults = defaultConfig;  

Extras

The module exports two useful functions which it uses internally: mergeDeep() and plainify(). See API docs for more information.

const nc = require('nested-config');

let obj1 = {
    a: 1,
    nested: {
        arr: [1, 2]
    }
};

let obj2 = {
    a: 2,
    nested: {
        arr: [3],
        foo: 'bar'
    }
};

nc.mergeDeep(obj1, obj2, {arrayBehavior: 1});
/* obj1:
{ 
    a: 2, 
    nested: {
        arr: [1, 2, 3],
        foo: 'bar'
    }
}
*/

let obj3 = nc.plainify(obj2);
/* obj3:
{
    a: 2, 
    'nested.arr': [3],
    'nested.foo': 'bar'
}
*/

JSDoc

API docs are available on the wiki.