App Config

In a rush?

If not - head over to the introduction.

# Installation

For yarn projects:

yarn add @app-config/main@2

For npm projects:

npm i @app-config/main@2

# Usage

You'll need a JSON Schema (opens new window) file before loading config. Add the file below to your project root.

.app-config.schema.yml

type: object
additionalProperties: false

required:
  - server
  - database

properties:
  server: { $ref: '#/definitions/Server' }
  database: { $ref: '#/definitions/Database' }

definitions:
  Server:
    type: object
    additionalProperties: false
    required: [port]
    properties:
      port: { $ref: '#/definitions/IpPort' }

  Database:
    type: object
    additionalProperties: false
    required: [host, port]
    properties:
      host: { type: string }
      port: { $ref: '#/definitions/IpPort' }
      database: { type: string }

  IpPort:
    type: integer
    minimum: 0
    maximum: 65535

Of course, you will want different options here. Build any JSON Schema that fits your use case.

Now, add an app-config file in the same directory.

.app-config.yml

server:
  port:
    $env:
      default: 3000
      production: 80

database:
  host: localhost
  port: 5432
  database: my-app

You've now seen an example of $env. This is governed by APP_CONFIG_ENV, NODE_ENV or ENV.

Now try to load the configuration that you just wrote, using the app-config CLI.

$ npx @app-config/cli vars
APP_CONFIG_SERVER_PORT=3000
APP_CONFIG_DATABASE_HOST="localhost"
APP_CONFIG_DATABASE_PORT=5432
APP_CONFIG_DATABASE_DATABASE="my-app"

From here, setup instructions differ for Node.js vs Webpack vs React Native. As an example, here's how a simple Node.js app works.

my-app.ts

import { config, loadConfig } from '@app-config/main';

async function main() {
  await loadConfig();

  // anywhere in your app, after loadConfig is complete and resolved
  console.log(config); // this is a JSON object, loaded from the YAML file
}

# Learn More

From this point on, there's lots to try out! Or, keep it simple and just use the basics.