Synchronous data access layer for your app configurations or feature flags as records in your existing database

This package provides an interface for storing data in your existing database with an in-memory cache layer for synchronous data access. The data could be feature flags, application configurations, etc. or anything else that you would need to change on the fly.

Supported databases at the moment are Postgres, MongoDB, and MySQL. The codebase follows a strategy pattern and devs can easily add new database implementations. Feel free to raise a pull request!

Install as a dependency

yarn add @siddiqus/app-settings

Example code:

import { AppSettings, MongoConfig } from '@siddiqus/app-settings';

// your database config, you can use your own configuration mechanism here
const config: MongoConfig = {
  dialect: 'mongodb',
  host: 'localhost',
  user: 'admin',
  password: 'password',
  database: 'testdb',
}; 

// this can be a singleton in your system
const appSettings = new AppSettings({
  dbConfig: config,
  tableName: 'app_settings_pg',
  refreshIntervalInSeconds: 300 // default interval is 300 seconds (5 minutes)
});

async function run() {
  await appSettings.init(); // this is needed to setup the db tables

  await appSettings.set({
    key: 'hey',
    value: { hey: 'there' },
    type: 'json',
  });

  await appSettings.set({
    key: 'someKey',
    value: 'boop',
    type: 'string', // string | boolean | json | number
  });

  const heyJson = appSettings.get('hey', {}); // notice this does not need await

  console.log(heyJson) // value is the { hey: there } object, or {} by default if the key does not exist 

On initializing the instance with your database configurations, few things happen:

1. It creates (if not existing) a table to store the settings
2. It will fetch the records from the table and store the formatted data in an in-memory cache

• Any time the set method is called, it will refresh the cache after the record is added/updated
• A process refreshes the cache every 5 minutes (this is configurable)
• Since the data is coming from in-memory, no need to await the get or getAll functions

This project is protected under the MIT License. For more details, refer to the reference website.