JS Config

An open source project to standardise JS configuration. It's designed for use in any browser, node.js or io.js.

Insallation & Compatability

This library is designed to be usable in Node.JS, IO.JS and all browsers in-the-wild. It's self-contained and dependency free. If you're old-school want to you can just copy & paste this into your code then grab JsConfig.js. If you're up-to-date with the rest of the world you'll want to use a package manager. You can install this module using NPM or Bower.

npm install --save js-config

or

bower install --save js-config

If you think other package managers should be supported (like the one for your favourite backend language) then feel free to raise a Pull Request for it - this library is designed to be assumption-free and should work with any backend language.

Usage Examples

Config should be pretty simple, hopefully simplicity is what you'll find when using JS Config! The basic examples are:

var myConfig = new JsConfig({
  someKey: 'someValue',
  collection: {
    item: 'a'
  }
});

myConfig.setDefault('collection.item', 'b');
myConfig.setDefault('collection.another', 'c');
myConfig.setDefault('collection.overriden', 'd');

myConfig.set('collection.overridden', 'e');

expect(myConfig.get('someKey')).toBe('someValue');
expect(myConfig.get('collection.item')).toBe('a');
expect(myConfig.get('collection.another')).toBe('c');
expect(myConfig.get('collection.overridden')).toBe('e');
expect(myConfig.get('collection.nothing')).toBe(undefined);
expect(myConfig.get('collection.nothing.this.would.usually.cause.problems')).toBe(undefined);

To use this with Node.JS or IO.JS you can do things like:

(using environment variables MY_OWN_PASSWORD=secret ONE_OPTIONAL_VALUE=abc)

var myConfig = new JsConfig({
  someKey: 'someValue',
  optionalValueTwo: 'defghi',
  collection: {
    item: 'a',
    thePassword: 'default password'
  }
});

expect(myConfig.get('collection.thePassword')).toEqual('default password');

myConfig.readFromObject(process.env, {
  collection: {
    thePassword: 'MY_OWN_PASSWORD'
  },
  optionalValueOne: 'ONE_OPTIONAL_VALUE',
  optionalValueTwo: 'ANOTHER_OPTIONAL_VALUE'
});

expect(myConfig.get('collection.thePassword')).toEqual('secret');
expect(myConfig.get('optionalValueOne')).toEqual('abc');
expect(myConfig.get('optionalValueTwo')).toEqual('defghi');

Equally in the browser you can use it to do things like:

(using configFromServer={oneUsePassword:'secret', {parent: {child: {stateBasedValue:'abc'}}})

var myConfig = new JsConfig({
  someKey: 'someValue',
  optionalValueTwo: 'defghi',
  collection: {
    item: 'a',
    thePassword: 'default password'
  }
});

expect(myConfig.get('collection.thePassword')).toEqual('default password');

myConfig.readFromObject(configFromServer, {
  collection: {
    thePassword: 'oneUsePassword'
  },
  optionalValueOne: 'parent.child.stateBasedValue',
  optionalValueTwo: 'parent.sibling.nonexistent'
});

expect(myConfig.get('collection.thePassword')).toEqual('secret');
expect(myConfig.get('optionalValueOne')).toEqual('abc');
expect(myConfig.get('optionalValueTwo')).toEqual('defghi');

This will give you an object which includes the environment variable values for MUST_BE_PRESENT, AN_ENV_VAR and NO_DEFAULT but blows up if one of them doesn't exist. It also includes ANOTHER_ENV_VAR and AN_OPTIONAL_FLAG if they're set or falls back to the specified defaults if they're not configured on the environment.

There are a load more usage examples at test/usageExamplesSpec.js

Revisions

v1.0.3:

• Tidying up semantics of defaults and overrides with objects (check usage examples for details)
• Fix for null values v1.0.2: Improved use cases for node/io (also available in the browser)
• readFromObject now allows you to use one name on environment variables and another name in your codebase. That's important for things like passwords - your environment variable may well be COMPANY_PROJECT_DB_PASS but your codebase might want to use config.get('db.password'). Previously you'd have to use config.get('COMPANY_PROJECT_DB_PASS') which leads to tightly coupled code & configuration - that was not a good thing.
• assertExists is a new way of managing mandatory configuration - you list the keys you can't manage without and a descriptive error gets thrown if they aren't set or are undefined. v1.0.1:
• Released to Bower v1.0.0: Initial release - the core functionality for managing configuration.
• Released to NPM

Contributions

Contributions are welcome, this project is maintained by Do Right Digital and it's designed to be small enough and generic enough that it can be used on any JS project. If you think there's a missing feature feel free to code it (with accompanying tests) or if just create some failing tests, then mark them as 'xit' and send a pull request.