layer-settings

Slim Settings-Manager on base of layers

npm install --save layer-settings

Usage

const Settings = require('layer-settings');

let settings = new Settings();

//Set default settings
settings.addLayer(
	{
		DEFAULT_SETTINGS
	}
);
//Add system settings
settings.addLayer('/etc/my-app/settings.json');
//Add user settings
settings.addLayer('~/.my-app/settings.json');
//Add command line parameters
settings.addLayers(args);

//Upper layers (added later) override values from lower layers
//Object values are merged recursive
//Arrays are overridden

//In this case first the static default settings,
//then the global settings in /etc
//then the user-specific settings in /home are read
//At the end the command line args are added


//(...)

let values = await settings.getValues();

//Do something with settings values

//(...)

await settings.save('~/.my-app/settings.json');
//Save settings modified by command line values

Example

const Settings = require('layer-settings');

let settings = new Settings();

//Set default settings
settings.addLayer(
	{
		a: 0,
		b: 1,
		c: [1, 2, 3],
		d:
		{
			a: 'A',
			b: []
		}
	}
);
//Add system settings
settings.addLayer('/etc/my-app/settings.json');
/* /etc/my-app/settings.json
{
	a: 42
}
*/

//Add user settings
settings.addLayer('~/.my-app/settings.json');
/* ~/.my-app/settings.json
{
	c: ['C'],
	d:
	{
		a: 'X',
		c: 1
	}
}
*/


//Add command line parameters
settings.addLayers(args);
/* Args
{
	a: 1337,
	b: undefined
}
*/

// (...)
let values = await settings.getValues();
/* values
{
	a: 1337, // from args
	b: 1, // from default settings, undefined values are ignored
	c: ['C'], // from user settings, arrays are overridden
	d: // objects are merged recursively
	{
		a: 'X', // from user settings
		b: [], // default settings
		c: 1 // from user settings
	}
}
*/

API

Settings.addLayer(values)

Add static layer

arguments

• values: object, static values

Settings.addLayer(path)

Add file layer

arguments

• path: string, settings file in JSON format

Settings.addLayer(layer)

Add raw layer-object inheriting from Settings.SettingsLayer

arguments

• layer: Settings.SettingsLayer

Settings.setLayers(layers)

Set layer-stack containing raw layer-objects inheriting from Settings.SettingsLayer

arguments

• layers: Settings.SettingsLayer[]

Settings.clearCache()

Clear cache. Called by Settings.addLayer and Settings.setLayers

Settings.getValues()

Reads/Processes settings values async or serves them from cache

returns

• Promise(settingsValues: object)

Settings.getValuesSync()

Reads/Processes settings values sync or serves them from cache

returns

• settingsValues: object

Settings.getRawValues()

Returns the current loaded settings values, no matter whether they are loaded or not

returns

• settingsValues: object

Settings.isLoaded()

Returns whether the settings are loaded

• loaded: boolean

Settings.save(path)

Saves settings values as JSON file async

arguments

• path: string, path to settings file to save to

returns

• Promise

Settings.saveSync(path)

Saves settings values as JSON file sync

arguments

• path: string, path to settings file to save to