yaconme v1.1.1

config-merger

The goal of this project is to provide a simple and lightweight way to merge a configuration with the environment variables or process arguments. In other words: With this you can override config entries based on environment and process.

Usage

const config = require('yaconme').config('config-prefix.')

API

The api of config-merger exposes only one method, namely .config

config(prefix, options?): any

'prefix'

The prefix by which to distinguish between relevant variables/arguments. Every argument you want to use must be prefixed with this exact string followed by the path seperator ('.' for process arguments and '_' for environment variables by default).

examples

Environment variables

PREFIX_port=3000

This will override the top level property 'port' with the value "3000"

options

Additional options like this:

export interface ConfigOptions {
  fallback?: any // your default configuration from which to start
  precedence?: Source[] // an order of precedence
  processArgs? // defaults to 'process.argv'
  processSeperator?: string // defaults to a '.'
  processEnv? // defaults to 'process.env',
  envSeperator?: string // defaults to a '_'
}
export enum Source {
  FALLBACK,
  ENVIRONMENT,
  PROCESS,
}

Precedence

Precedence specifies which Source overwrites which.

There is a default order that overwrites a passed in config with the environment and the environment with the process arguments. fallback <- environment <- process

However, you can specify any other order.

Nested objects/deep merging

It is possible to deeply overwrite values instead of a whole object like so (given the prefix is config)

It is important to note the path seperators of process arguments can differ from those of environment variables!

my-app config.some.nested.value=overwritten config.some.other.path alsoOverwritten