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.
It does not support multiple processes writing to the same store.
I initially made this tool to let command-line tools persist some data.
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', 'π¦');
console.log(config.get('unicorn'));
//=> 'π¦'
// 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
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
Type: object
defaults
Type: object
Default values for the config items.
Note: The values in defaults
will overwrite the default
key in the schema
option.
schema
Type: object
JSON Schema to validate your config data.
Under the hood, the JSON Schema validator ajv is used to validate your config. We use JSON Schema draft-07 and support all validation keywords and formats.
You should define your schema as an object where each key is the name of your data's property and each value is a JSON schema used to validate that property. See more here.
Example:
const Conf = require('conf');
const schema = {
foo: {
type: 'number',
maximum: 100,
minimum: 1,
default: 50
},
bar: {
type: 'string',
format: 'url'
}
};
const config = new Conf({schema});
console.log(config.get('foo'));
//=> 50
config.set('foo', '1');
// [Error: Config schema violation: `foo` should be number]
Note: The default
value will be overwritten by the defaults
option if set.
migrations
Type: object
You can use migrations to perform operations to the store whenever a project version is upgraded.
The migrations
object should consist of a key-value pair of 'version': handler
. The version
can also be a semver range.
Example:
const Conf = require('conf');
const store = new Conf({
migrations: {
'0.0.1': store => {
store.set('debugPhase', true);
},
'1.0.0': store => {
store.delete('debugPhase');
store.set('phase', '1.0.0');
},
'1.0.2': store => {
store.set('phase', '1.0.2');
},
'>=2.0.0': store => {
store.set('phase', '>=2.0.0');
}
}
});
Note: The version the migrations use refers to the project version by default. If you want to change this behavior, specify the
projectVersion
option.
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 or if it doesn't have a name defined within it.
projectVersion
Type: string
Default: The version
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 or if it doesn't have a version defined within it.
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. By default, it will pick the optimal location by adhering to system conventions. You are very likely to get this wrong and annoy users.
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
This can be used to secure sensitive data if the encryption key is stored in a secure manner (not plain-text) in the Node.js app. For example, by using node-keytar
to store the encryption key securely, or asking the encryption key from the user (a password) and then storing it in a variable.
In addition to security, this could be used 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: false
The config is cleared if reading the config file causes a SyntaxError
. This is a good behavior for unimportant data, 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.
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
.
accessPropertiesByDotNotation
Type: boolean
Default: true
Accessing nested properties by dot notation. For example:
const Conf = require('conf');
const config = new Conf();
config.set({
foo: {
bar: {
foobar: 'π¦'
}
}
});
console.log(config.get('foo.bar.foobar'));
//=> 'π¦'
Alternatively, you can set this option to false
so the whole string would be treated as one key.
const Conf = require('conf');
const config = new Conf({accessPropertiesByDotNotation: false});
config.set({
`foo.bar.foobar`: 'π¦'
});
console.log(config.get('foo.bar.foobar'));
//=> 'π¦'
watch
type: boolean
Default: false
Watch for any changes in the config file and call the callback for onDidChange
or onDidAnyChange
if set. This is useful if there are multiple processes changing the same config file.
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 forβ¦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.
.reset(...keys)
Reset items to their default values, as defined by the defaults
or schema
option.
Use .clear()
to reset all items.
.has(key)
Check if an item exists.
.delete(key)
Delete an item.
.clear()
Delete all items.
This resets known items to their default values, if defined by the defaults
or schema
option.
.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
.
Returns a function which you can use to unsubscribe:
const unsubscribe = conf.onDidChange(key, callback);
unsubscribe();
.onDidAnyChange(callback)
callback
: (newValue, oldValue) => {}
Watches the whole config object, calling callback
on any changes.
oldValue
and newValue
will be the config object before and after the change, respectively. You must compare oldValue
to newValue
to find out what changed.
Returns a function which you can use to unsubscribe:
const unsubscribe = conf.onDidAnyChange(callback);
unsubscribe();
.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
configstore
?
How is this different from 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 Conf = require('conf');
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