determination

determination

Configuration resolver. determination loads a JSON configuration file, resolving against criteria using confidence and shortstop protocol handlers.

In addition, determination supports javascript style comments in your JSON using shush.

Note: determination borrows heavily from confit, but prefers confidence for resolving environment as well as other criteria for filtering.

Usage

const Determination = require('determination');

Determination.create(options)

• options (Object) - an options object containing:
  • config (String) - required path to a JSON configuration.
  • criteria (Object) - optional resolution criteria. See confidence. Minimally will always contain process.env under the key env.
  • protocols (Object) - optional mapping of protocols for shortstop.
  • defaults (Object | String) - optional default configuration values.
  • overrides (Object | String) - optional override configuration values.
• returns - a resolver.

resolver.resolve([callback])

• callback (Function) - an optional callback.
• returns - a promise if callback is not provided.

const Determination = require('determination');
const Path = require('path');
const Handlers = require('shortstop-handlers');

const config = Path.join('.', 'config', 'config.json');

const resolver = Determination.create({
    config,
    protocols: {
        require: Handlers.require(Path.dirname(config))
    }
});

resolver.resolve((error, config) => {
    //config.get
    //config.set
});

Config API

• get(string: key) - returns the value for the given key, where a dot-delimited key may traverse the configuration store.
• set(string: key, any: value) - sets the given value on the given key, where dot-delimited key may traverse the configuration store.
• merge(object: value) - merges the given value into the configuration store.
• use(object: store) - merges the given store into the configuration store.
• data - accessor for a clone of the underlying store data (modifying this will not modify store).

config.set('some.key.name', 'value');
config.merge({ some: { key: other: 'another value' }});
config.get('some.key.other'); //'another value'

Shortstop Protocol Handlers

Two protocol handlers are enabled by default:

• import:path - merges the contents of a given file, supporting comments (unlike require).
• config:key - copies the value under the given key (supporting dot-delimited) to the key it is declared on.

Resolution Order

Configuration file contents are resolved in the following order:

1. Resolve defaults against protocols.
2. Merge defaults with config.
3. Resolve merged config against protocols.
4. Resolve overrides against protocols.
5. Merge overrides into config.
6. Resolve config against config: protocol.

Changelog

1.3.0

• config.data returns a clone of the underlying store data.