Implementing Feature Flags from Scratch - Part 5

In this video I will show you how to create a flags' loader for MongoDB. We will create a Mongoose schema and model for our flags. For testing, we will use MongoDB Memory Server. As a bonus, I will show you how we are setting Mongoose as a peer dependency.

Our goal in this series is to develop a complete TypeScript solution (minus the front-end, at least for now) to manage and use Feature Flags (also known as Feature Toggles) without using any existing frameworks or tools to handle them (no third-party libs). When finished, we will have functions for checking flag’s status based on the flag's name and user's group, caching and auto-refreshing, loaders for different data sources, and easy support for switching between new and legacy features. We are using Lerna (monorepo tool), Verdaccio (private NPM proxy registry), Vitest (Unit Test Framework), Fastify (Web Framework, so we can create our back-end REST feature flag service) and MongoDB (NoSQL) as our database.

?If you want to write any comments, you can do it in English or Portuguese. I'll keep the replies in Portuguese and translate them to English.

★ Implementing Feature Flags From Scratch Series - Part 1: https://youtu.be/73NQuTACyus
★ Implementing Feature Flags From Scratch Series - Part 2: https://youtu.be/EGdYfnhzni4
★ Implementing Feature Flags From Scratch Series - Part 3: https://youtu.be/p6cKvQY6zMY
★ Implementing Feature Flags From Scratch Series - Part 4: https://youtu.be/c_J7BNOobgI

★ Installing NPM packages in you computer with Verdaccio NPM Proxy Registry: https://youtu.be/RiWpWcf2GQc

?Our code repo: https://github.com/marcellothiry/feature-flags

► Lerna (Monorepo Tool): https://lerna.js.org/
► Verdaccio (NPM Proxy Registry): https://verdaccio.org/
► Vitest (Unit Test Framework): https://vitest.dev/
► Fastify (Web Framework): https://www.fastify.io/
► MongoDB (NoSQL database): https://www.mongodb.com/

► LinkedIn: https://www.linkedin.com/in/marcello-thiry-b29216a/

#marcellothiry #fromdev2dev #typescript #mongodb #mongoose #vitest

► Key moments:
0:00 Intro.
00:40 Adding types using generics for our functions and options.
02:28 Implementing the method to get the feature based on given options.
03:27 Testing our method with sync and async features.
06:45 Adding the override function as a new options field and reviewing our get feature method.
08:20 Testing the last changes.
11:34 A get feature method for async features.