Config Loader

Get ready to load all the configuration into a single plane old javascript object from any directory and with file format priority, defaults and overwriting.

Install

npm install @universal-packages/config-loader

Global methods

loadConfig(location: string, [options])

Given a configuration location reads deeply into it and get all the contents of the configuration files there into a plain old javascript object.

import { loadConfig } from '@universal-packages/config-loader'

const config = loadConfig('./config')

console.log(config)

Lets say ./config looks like this in disk:

config
  |- database.yaml
  |- redis.json
  |- secrets
      |- api.yaml
      |- github.js

We will end up with something like

{
  "database": {
    "host": "localhost",
    "post": 5432
  },
  "redis": {
    "host": "localhost",
    "post": 6380
  },
  "secrets": {
    "api": {
      "key": "n35jnk36n4j6nkj"
    },
    "github": {
      "key": "kl456jk456kj45n6"
    }
  }
}

Options

• callback TraverseCallback A function to pass to the directory-traversal, call for every directory mapped, use this to decide if the config loading should continue or modify the directory map before loading files in it.

• cleanOrphanReplaceable boolean Replaceable strings that are not found in the environment variables will be removed from the final values.

  import { loadConfig } from '@universal-packages/config-loader'
  
  const config = await loadConfig('./config', { selectEnvironment: 'staging' })
  
  console.log(config)

  Lets say ./config/redis.yaml looks like this:

  default:
    port: 6380
  development:
    host: localhost
    dev: true
  production:
    host: 45.60.129.1

  We will end up with something like

  {
    "redis": {
      "host": "localhost",
      "post": 6380,
      "dev": true
    }
  }

• conventionPrefix string If you want to use .config.<ext> as a prefix for your files you can set this option to config.

• formatPriority ['json' | 'yaml' | 'yml' | 'js' | 'ts'] If there are 2 files with the same name but with different extension? which one should be prioritized to load?

• selectEnvironment string | boolean If you want your files to be post processed after loaded with a selection of an environment section you can specify the name of the environment to select or pass true to automatically set from NODE_ENV.

loadFileConfig(location: string, [options])

Given a base file location it prioritizes and loads the file content into a plain old javascript object.

Example if there are two files jest.js and jest.yml in your root directory the following script will load the jest.js contents over the jest.yml ones.

import { loadFileConfig } from '@universal-packages/config-loader'

const config = await loadConfig('./jest', { formatPriority: ['js', 'yml'] })

console.log(config)

Options

• cleanOrphanReplaceable boolean Replaceable strings that are not found in the environment variables will be removed from the final values.

• formatPriority ['json' | 'yaml' | 'yml' | 'js' | 'ts'] If there are 2 files with the same name but with different extension? which one should be prioritized to load?

• selectEnvironment string If you want your files to be post processed after loaded with a selection of an environment section you can specify the name of the environment to select.

Environment variables

Config loader will try to match strings inside the configuration files with a replacement pattern and assign the value of an environment variable if it exists.

Lets say ./config/redis.yaml looks like this:

default:
  port: 6380
development:
  host: localhost
  dev: true
production:
  host: '{{ REDIS_HOST }}'

We will end up with something like if REDIS_HOST is set with www.redis.com

{
  "redis": {
    "host": "www.redis.com",
    "post": 6380
  }
}

deepMergeConfig(target: Object, [...sources])

It will merge all the sources into the target config object deeply.

import { deepMergeConfig } from '@universal-packages/config-loader'

const target = {
  a: {
    b: {
      c: 1
    }
  }
}

const source = {
  a: {
    b: {
      d: 2
    }
  }
}

const result = deepMergeConfig(target, source)

// result = {
//   a: {
//     b: {
//       c: 1,
//       d: 2,
//     },
//   },
// }

Typescript

This library is developed in TypeScript and shipped fully typed.

Contributing

The development of this library happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving this library.

• Code of Conduct
• Contributing Guide

License

MIT licensed.