config loader

config, hjson, json, node
npm install @streetstrider/bridge@1.0.0



bridge is a simple Node.js config loader with some conventions.

how it works

import bridge from '@streetstrider/bridge'

var cfg = bridge(options)

bridge will find package root from process.cwd() then load configs following next principles:

1. Load package.json and mount it to cfg._.package.

2. Load release.json (if present) and mount it to cfg._.release. This file is produced by metalbox.

3. bridge understands both JSON and HJSON files, with preference to HJSON. When resolving user config foo, bridge will look for foo.hjson, foo.json and foo respectively.

4. Load main config from one of cfg/{cfg.hjson,cfg.json,cfg} and mount it to cfg._.main.

5. Determine in which mode bridge is running.

5A. If release.json is present, bridge is running in a production mode. In that case load instance config (if present) from one of cfg/{<instance>.hjson,<instance>.json,<instance>} and mount it to cfg._.instance. Actual instance is determined by release.json instance field.

5B. If no release.json is present, bridge is running in dev mode. In that case load dev config (if present) from one of cfg/{dev.hjson,dev.json,dev} and mount it to cfg._.dev.

5C. Both instance and dev configs are meant to share the same structure (or schema) as main config. That allows to merge them to main config. Such kind of merging open way for flexible config management both in dev and production. Having release.json, instance configs and gitignored dev config we can completely get rid of crappy ENV variables and other like solutions.

5D. Update main config recursively (lodash.merge) with instance/dev config and mount it to cfg._.merged.

6. After all configs are all set, create one unite config for short access and conveniece. Merge cfg._.package, cfg._.release and cfg._.merged and mount it to cfg._.all.

6A. Having all package, release, instance, dev, merged and all configs separately allows to precise options picking. all and merged are recommended in the majority of the cases.

6B. Make all config accessible directly on cfg, i.e merge it to the cfg itself. If you have port option in your cfg.hjson it will be accessible via cfg._.main.port, cfg._.merged.port, cfg._.all.port or simply cfg.port. The last form is OK but can lead to conflicts in rare cases when you're not fully understand your own config schema. In that cases use precision namespaces (merged is the good way).

7. bridge will also expose some helper functions ontop of it (like cfg.get). If that conflicts with your config schema, just access underlying merged or all namespaces directly or use helpers on its own to access such conflicting names.

helpers API

cfg.get(path: string | string[], defval: any) — retrieve option from all by string / dotpath / array path (object-path#get). If option is not present defval is used (or undefined by default).

cfg.nsget(namespace: string, path: string | string[], defval: any) — retrieve option from certain namespace. Namespaces:

  • package
  • release
  • main
  • instance
  • dev
  • merged
  • all


  • dir: string = 'cfg/' — directory where config's family live (main/instance/dev configs). Path may be relative to package's root.
  • file: string = 'cfg' — main config file. bridge will always look up for {<file>.hjson,<file>.json,<file>}.


ISC, © 2018, Strider.