# Day 173 of Learning MERN Stack

> Source: <https://dev.to/ali_hamza_589ec7b3eb6688d/day-173-of-learning-mern-stack-36b5>
> Published: 2026-08-16 07:25:32+00:00

Hello Dev Community! 👋

It is officially **Day 173** of my full-stack engineering track! Today, I explored one of the core mechanisms that make **TypeScript** powerful and developer-friendly: **Type Inference vs. Type Annotations**! 📘⚡

Understanding when to let the TypeScript compiler infer types automatically versus declaring them explicitly makes codebases cleaner and more maintainable.

As captured in my code editor setup (** index.ts**):

``` js
typescript
  let drink = "Chai peyo"; // Inferenced as type string
  // drink = 0; // Error: Type 'number' is not assignable to type 'string'.
```