npc

Use Networking Parameters Containers, or NPC instances, for improved type-safety and consistency in your code when developing JavaScript applications.

For the best experience and results, use npc together with dotenv. Like dotenv, npc embraces the Twelve-Factor App methodology's principle of storing configuration in the environment separate from code. npc takes this even further, by also keeping the fallback defaults, if configuration is missing, separate from the code and the main application logic.

npc has zero dependencies.

What are networking parameters?

To give you an idea, here are some networking parameters in an .env file:

SERVER_HOST=localhost
SERVER_PORT=3000

API_HOST=exampleapi.org
API_SECURE=true

Usage

Let's say we need some parameters in order to perform a fetch.

require("dotenv").config() // loading the networking parameters from the .env file

const apiParams = new NPC("API"),
      query = "somecontent"

fetch(`${apiParams.protocol}://${apiParams.host}/${query}`)
	.then(res => /*do something with the response*/)

// or

const { protocol, host } = new NPC("API")
const query = "somecontent"

fetch(`${protocol}://${host}/${query}`)
	.then(res => /*do something with the response*/)

npc falls back to defaults if a parameter wasn't defined. It guesses what defaults to provide based on the parameters that were defined – whether they are accessed or not – in conjuction with a set of presets.

In the example above, apiParams.protocol will return "https", even though there was no API_PROTOCOL=https entry in the .env file. npc defaults to the HTTP protocol if no protocol is specified and knows to return https instead of http because API_SECURE specified as true.

Assumptions

npc is built around the following assumptions:

1. Your networking parameters can be found in the process.env object.
2. You follow these conventions when naming the parameters:
   1. the name is SCREAMING_SNAKE_CASE
   2. the name can be dissected into two parts: <context>_<type>, e.g. API_HOST where API is the context and HOST is the type

API

The constructor takes two arguments:

• context – specifies which set of networking parameters you want dedicate the container to. If you don't supply this parameter, it is assumed you only have one set of networking parameters, defined as just the types of parameters they represent, no context prepended to their names.

• preset – if you want to explicitly specify what preset of defaults to fall back to, you can specify that here, as a string. This is optional.

  const dbParams = new NPC("DB", "mongodb")

Types, defaults and presets

Out of the box, npc supports following parameter types:

Type	Default
protocol	"http"
host	undefined
port	80
secure	false
name	undefined

Alternative default values originate from presets:

• HTTPS

  Type	Default
  protocol	"https"
  port	443
  secure	true

• MongoDB

  Type	Default
  protocol	"mongodb"
  port	27017

As of now (v0.1.0) you can't provide your own types and presets, but it's an upcoming feature, so stay tuned.

Of course, feel free to fork and add your own out-of-the-box types and presets to make npc satisfy your needs, and if you do, send a pull request with what you added to help grow npc's out of the box functionality!

If there's anything you want to point out about any aspect of the project (even grammar used in this readme), please do point out. All feedback is appreciated. I'm fairly new to this game and I have a lot to learn.