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Hands-On Introduction to Testing with Jest
Rating: 3.5 out of 5(1 rating)
147 students

Hands-On Introduction to Testing with Jest

Guide to testing JavaScript and TypeScript apps with Jest from scratch
Created byLukasz Kallas
Last updated 5/2026
English

What you'll learn

  • Understand what testing is and why it's important in software development
  • Install and configure Jest in JavaScript and TypeScript projects
  • Write unit tests for functions and modules using Jest
  • Use Jest matchers and assertions to verify code behaviour
  • Test asynchronous code including promises and async/await
  • Work with mocks and spies to isolate code under test

Course content

3 sections20 lectures4h 42m total length
  • Welcome!3:04
  • Join Our Community0:04
  • What is Jest & Why to Use it7:53
  • Setup7:19
  • Project10:51

Requirements

  • Basic JavaScript knowledge including functions, objects, arrays, and ES6 syntax
  • Familiarity with Node.js and npm
  • Basic understanding of asynchronous JavaScript (promises and async/await)
  • Basic TypeScript knowledge is helpful but not required

Description

This hands-on course provides a practical introduction to testing JavaScript and TypeScript applications using Jest, one of the most popular testing frameworks in the JavaScript ecosystem.

If you’ve ever wanted to write reliable tests, catch bugs earlier, and build more confidence in your code, this course is for you.

We focus on learning by doing. There are no theory-heavy slides or long explanations. Instead, you’ll start writing real tests from the very first lessons and build practical skills that you can immediately use in your own projects.

You’ll begin by setting up Jest in a project and understanding how the testing workflow works. From there, we’ll cover unit testing for functions and modules, working with assertions and matchers, and understanding how to read test results.

As the course progresses, you’ll learn how to test asynchronous code using promises and async/await, use mocks and spies to isolate dependencies, and write cleaner, more maintainable test suites.

We’ll also cover testing TypeScript code, handling edge cases, organizing tests properly, and debugging failing tests effectively.

Throughout the course, you’ll work with practical examples based on real-world coding scenarios, helping you understand not just how to write tests, but why they matter.

By the end of this course, you’ll feel confident using Jest in your daily workflow and adding automated testing to both small and large projects.

This course is a great fit if you are:

  • A beginner developer learning professional coding practices

  • A JavaScript or TypeScript developer who wants to start testing

  • A backend or frontend developer improving code quality

  • Anyone who wants to ship more reliable applications

If you want a clear, beginner-friendly, and hands-on introduction to testing with Jest, this course is for you.

Who this course is for:

  • JavaScript and TypeScript developers who want to learn testing
  • Frontend and backend developers looking to improve code quality
  • Anyone who wants to understand how to write and run tests with Jest