conf

What is conf?

The 'conf' npm package is a simple yet powerful configuration management tool for Node.js applications. It allows you to easily store and retrieve configuration data, manage defaults, and handle schema validation. The data is stored in a JSON file, making it easy to read and modify.

What are conf's main functionalities?

Store and Retrieve Configuration Data

This feature allows you to store and retrieve configuration data easily. The data is stored in a JSON file, and you can set and get values using simple methods.

const Conf = require('conf');
const config = new Conf();

// Set a value
config.set('unicorn', '🦄');

// Get a value
console.log(config.get('unicorn'));
//=> '🦄'

Manage Default Values

You can define default values for your configuration settings. If a key is not set, the default value will be returned.

const Conf = require('conf');
const config = new Conf({
  defaults: {
    foo: 'bar'
  }
});

console.log(config.get('foo'));
//=> 'bar'

Schema Validation

You can define a schema for your configuration to ensure that the data meets certain criteria. This helps in maintaining data integrity and consistency.

const Conf = require('conf');
const schema = {
  type: 'object',
  properties: {
    foo: {
      type: 'string'
    },
    bar: {
      type: 'number',
      minimum: 0
    }
  }
};
const config = new Conf({ schema });

config.set('foo', 'baz');
config.set('bar', 42);

console.log(config.get('foo'));
//=> 'baz'
console.log(config.get('bar'));
//=> 42

Other packages similar to conf

configstore

Configstore is another package for managing configuration data in Node.js applications. It provides similar functionality to 'conf', such as storing and retrieving data, managing defaults, and handling schema validation. However, 'conf' offers a more modern API and better TypeScript support.

node-persist

Node-persist is a simple, zero-dependency, key-value storage library for Node.js. It provides persistent storage for configuration data, similar to 'conf'. However, 'conf' offers more advanced features like schema validation and default values management.

nconf

Nconf is a hierarchical configuration manager for Node.js. It supports multiple configuration sources such as command-line arguments, environment variables, and JSON files. While 'nconf' is more flexible in terms of configuration sources, 'conf' is simpler and easier to use for most use cases.

README

conf

Simple config handling for your app or module

All you have to care about is what to persist. This module will handle all the dull details like where and how.

If you need this for Electron, check out electron-store instead.

Install

$ npm install conf

Usage

const Conf = require('conf');

const config = new Conf();

config.set('unicorn', '🦄');
console.log(config.get('unicorn'));
//=> '🦄'

// Use dot-notation to access nested properties
config.set('foo.bar', true);
console.log(config.get('foo'));
//=> {bar: true}

config.delete('unicorn');
console.log(config.get('unicorn'));
//=> undefined

Or create a subclass.

API

Changes are written to disk atomically, so if the process crashes during a write, it will not corrupt the existing config.

Conf([options])

Returns a new instance.

options

defaults

Type: Object

Config used if there are no existing config.

configName

Type: string
Default: config

Name of the config file (without extension).

Useful if you need multiple config files for your app or module. For example, different config files between two major versions.

projectName

Type: string
Default: The name field in the package.json closest to where conf is imported.

You only need to specify this if you don't have a package.json file in your project.

cwd

Type: string
Default: System default user config directory

You most likely don't need this. Please don't use it unless you really have to.

Overrides projectName.

The only use-case I can think of is having the config located in the app directory or on some external storage.

encryptionKey

Type: string Buffer TypedArray DataView
Default: undefined

Note that this is not intended for security purposes, since the encryption key would be easily found inside a plain-text Node.js app.

Its main use is for obscurity. If a user looks through the config directory and finds the config file, since it's just a JSON file, they may be tempted to modify it. By providing an encryption key, the file will be obfuscated, which should hopefully deter any users from doing so.

It also has the added bonus of ensuring the config file's integrity. If the file is changed in any way, the decryption will not work, in which case the store will just reset back to its default state.

When specified, the store will be encrypted using the aes-256-cbc encryption algorithm.

fileExtension

Type: string
Default: json

Extension of the config file.

You would usually not need this, but could be useful if you want to interact with a file with a custom file extension that can be associated with your app. These might be simple save/export/preference files that are intended to be shareable or saved outside of the app.

clearInvalidConfig

Type: boolean
Default: true

The config is cleared if reading the config file causes a SyntaxError. This is a good default, as the config file is not intended to be hand-edited, so it usually means the config is corrupt and there's nothing the user can do about it anyway. However, if you let the user edit the config file directly, mistakes might happen and it could be more useful to throw an error when the config is invalid instead of clearing. Disabling this option will make it throw a SyntaxError on invalid config instead of clearing.

serialize

Type: Function
Default: value => JSON.stringify(value, null, '\t')

Function to serialize the config object to a UTF-8 string when writing the config file.

You would usually not need this, but it could be useful if you want to use a format other than JSON.

deserialize

Type: Function
Default: JSON.parse

Function to deserialize the config object from a UTF-8 string when reading the config file.

You would usually not need this, but it could be useful if you want to use a format other than JSON.

projectSuffix

Type: string
Default: nodejs

You most likely don't need this. Please don't use it unless you really have to.

Suffix appended to projectName during config file creation to avoid name conflicts with native apps.

You can pass an empty string to remove the suffix.

For example, on macOS, the config file will be stored in the ~/Library/Preferences/foo-nodejs directory, where foo is the projectName.

Instance

You can use dot-notation in a key to access nested properties.

The instance is iterable so you can use it directly in a for…of loop.

.set(key, value)

Set an item.

The value must be JSON serializable. Trying to set the type undefined, function, or symbol will result in a TypeError.

.set(object)

Set multiple items at once.

.get(key, [defaultValue])

Get an item or defaultValue if the item does not exist.

.has(key)

Check if an item exists.

.delete(key)

Delete an item.

.clear()

Delete all items.

.onDidChange(key, callback)

callback: (newValue, oldValue) => {}

Watches the given key, calling callback on any changes. When a key is first set oldValue will be undefined, and when a key is deleted newValue will be undefined.

.size

Get the item count.

.store

Get all the config as an object or replace the current config with an object:

conf.store = {
	hello: 'world'
};

.path

Get the path to the config file.

FAQ

How is this different from configstore?

I'm also the author of configstore. While it's pretty good, I did make some mistakes early on that are hard to change at this point. This module is the result of everything I learned from making configstore. Mainly where the config is stored. In configstore, the config is stored in ~/.config (which is mainly a Linux convention) on all systems, while conf stores config in the system default user config directory. The ~/.config directory, it turns out, often have an incorrect permission on macOS and Windows, which has caused a lot of grief for users.

Can I use YAML or another serialization format?

The serialize and deserialize options can be used to customize the format of the config file, as long as the representation is compatible with utf8 encoding.

Example using YAML:

const yaml = require('js-yaml');

const config = new Conf({
	fileExtension: 'yaml',
	serialize: yaml.safeDump,
	deserialize: yaml.safeLoad
});

Related

• electron-store - Simple data persistence for your Electron app or module
• cache-conf - Simple cache config handling for your app or module

License

MIT © Sindre Sorhus