TypeScript Introduction

What TypeScript is and why teams use it.

✍️ 3 exercises + code challenge in this lesson

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TypeScript is JavaScript with types, created by Microsoft. TypeScript code is compiled ("transpiled") into plain JavaScript, so it runs anywhere JavaScript runs.

Why TypeScript?

Find bugs while you type, before the code runs.
Better auto-complete and refactoring in editors.
Types document what functions expect and return.

Angular, Next.js, NestJS and most large React projects use TypeScript.

The editor compiles your TypeScript in the browser and shows console.log output.

Key Takeaways: TypeScript Introduction

Mastering TypeScript Introduction helps you write clean and reliable TypeScript code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.

TypeScript Introduction Code Example

TypeScript

const message: string = "Hello, TypeScript!";
console.log(message);

Output

Hello, TypeScript!

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TypeScript Introduction Practice Exercises

Check what you learned in “TypeScript Introduction”.

/ 3 solved

Fill in the blank

Add a type annotation for a string.

const title = "Hello";

✓ Correct! Not quite. Try again.

Multiple choice

What does TypeScript compile into?

JavaScript Java WebAssembly Python

✓ Correct! Not quite. Try again.

Code challenge

Declare a constant course of type string with the value "TypeScript" and log it.

Write the code in the live editor. Your answer is checked automatically.

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to save your exercise progress.

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Mark it complete to track your progress.

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TypeScript Get Started

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TypeScript Introduction

Why TypeScript?

💡 Key Takeaways: TypeScript Introduction

TypeScript Introduction Code Example

TypeScript Introduction Practice Exercises

Key Takeaways: TypeScript Introduction