Rust 101 — Fundamentals

Welcome to Rust 101

You already know TypeScript. You understand types, functions, and how to build real software. This module uses that knowledge as a bridge — every concept is introduced by comparing it to something you already know, then showing the Rust way.

What you will learn

This module covers the core building blocks of Rust that map to everyday TypeScript patterns:

Variables — let, let mut, const, shadowing, and type inference
Functions — typed parameters, return types, and expression-oriented syntax
Control flow — if as an expression, match, loop, while, for
Structs — the Rust alternative to classes and interfaces
Enums — algebraic data types and exhaustive pattern matching
Collections — Vec, HashMap, arrays, tuples, slices
Option and Result — replacing null/undefined and try/catch
Modules and crates — the Rust equivalent of ESM and npm

By the end you will have the vocabulary to read and write real Rust programs.

Your first side-by-side

Both programs greet the user. The structure is similar, but Rust is compiled, statically typed, and has no runtime — println! is a macro that resolves format strings at compile time.

const name = "TypeScript developer";
console.log(`Hello, ${name}! Welcome to Rust.`);

fn main() {
    let name = "TypeScript developer";
    println!("Hello, {}! Welcome to Rust.", name);
}

Try it

Run the Rust snippet above directly in your browser.

Open in Rust Playground

fn main() {
    let name = "TypeScript developer";
    println!("Hello, {}! Welcome to Rust.", name);
}

In Rust, what is println! ? A built-in function from the standard library A macro that resolves format strings at compile time A method on the String type A global variable

What is the entry point of every Rust binary program? start() init() main() run()