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Beginner · TypeScript

TypeScript for Beginners

A friendly first course in TypeScript for people who know a little JavaScript. Learn types, interfaces, unions, and generics, and see how TypeScript helps you catch mistakes before your website ever loads.

TypeScript is JavaScript with a type system on top. In this course you will learn what types are, why they matter as websites grow, and how to describe your data with interfaces, unions, and generics. You will also see how TypeScript compiles down to plain JavaScript and where it fits in a real web project. Every idea is explained with short, readable examples that build on the JavaScript you already know.

Beginner 12 lessons ~91 min TypeScript
Start the course
01

Why TypeScript?

Find out what TypeScript is, why types make bigger projects easier, and how to give your first variables and functions their own types.

3 lessons
  1. 1 What Is TypeScript? JavaScript with a safety net 6 min
  2. 2 The Three Basic Types string, number, and boolean 7 min
  3. 3 Typing Variables and Functions Tell TypeScript what goes in and what comes out 8 min
02

Shaping Your Data

Give types to the arrays and objects that hold your real data, describe object shapes with interfaces, and handle values that might be missing.

3 lessons
  1. 4 Arrays with Types A list where everything belongs 7 min
  2. 5 Objects and Interfaces Describe the shape of your data 9 min
  3. 6 Optional Properties and Defaults When a value might not be there 8 min
03

Flexible Types

Learn union and literal types for values with a few allowed options, let type inference do the boring work, and compare enums with unions.

3 lessons
  1. 7 Union Types and Literal Types This or that, but nothing else 9 min
  2. 8 Type Inference TypeScript often just knows 6 min
  3. 9 Enums vs Unions Two ways to say 'pick from this list' 8 min
04

TypeScript in the Real World

Take a gentle first look at generics, see exactly how TypeScript turns into JavaScript, and learn where it fits when building a real website.

3 lessons
  1. 10 A Gentle Look at Generics One function, many types 10 min
  2. 11 How TypeScript Becomes JavaScript The compile step, demystified 7 min
  3. 12 Where TypeScript Fits in a Website Your map of the real world 6 min