yml-config-reader - YAML Configuration Reader for Node.js

This plugin provides a way to configure your node project based on YAML files. The configuration reader itself is really small since almost everything is done by js-yaml or lodash. You can use it as an alternative to dotenv with the advantage that you can provide default settings and use the more powerful YAML format.

Installation

$ npm install yml-config-reader --save-dev

Usage

Create a file config.default.yml with your configuration. Example:

app1:
    serviceUrl: app1.api.com
db:
    name: test-db
stage: qa

To read this config file, you need the following javascript code.

const configReader = require('yml-config-reader')

const config = configReader.getByFiles('config.default.yml')
console.log(config.db.name) // prints test-db

The method getByFiles can take an arbitrary number of config files that are merged together with values in later files taking precedence. Example: getByFiles('config.default.yml', 'config.qa.yml')

As an alternative you can pass an environment variable to your node application which then can be used to pick up the according config files. Example:

$ STAGE=test node yourscript.js

const configReader = require('yml-config-reader')

const config = configReader.getByEnv(process.env.STAGE)
console.log(config.db.name) // prints test-db

The command getByEnv takes a parameter environment and uses this one to search for the file config.${environment}.yml. This method always checks if a file called config.default.yml exists and uses configuration values that are defined in that file as defaults.

You can also specify a folder name if you wish to store your config files separately. Example:

const configReader = require('yml-config-reader')

configReader.getByEnv(process.env.STAGE, 'config') // uses the 'config' folder
configReader.getByFiles('config/config.default.yml', 'config/config.qa.yml')

Compound / Nested Variables

It is possible to reuse existing properties in a config file as values for other properties. You can use the syntax ${varName} if you wish that the string ${varName} shall be substituted with the actual value of the property varName. Example:

baseUrl: app.company.com

app1:
    restUrl: app1.${baseUrl}

If you use multiple configuration files this substitution takes all properties across all files into account.

Usage with webpack

This plugin can also be used with webpack, for example if you want to use global variables in your web application that shall be stored in YAML configuration files. Here you can find an example for your webpack.config.js.

const webpack = require('webpack')
const configReader = require('yml-config-reader')

module.exports = (env) => {
  const config = configReader.getByEnv(env.stage || 'test')

  return {
    plugins: [
      new webpack.DefinePlugin({
        "process.env": JSON.stringify(config)
      })
    ]
  }
}

The config map is then available in your script files by using the variable process.env.

This example uses webpack environment variables to pass a proper value to the function getByEnv. You can pass this value directly via the command line with npm start -- --env.stage=qa.