Science Knowings: JavaScript Course For Social Media

Test-Driven Development (TDD) with JavaScript

What is Test-Driven Development (TDD)?

In TDD, you write tests first to define the expected behavior of your code. Then you write the implementation code to pass those tests. This helps ensure correctness and quality.

Benefits of TDD

Faster Development: Tests provide a clear plan and guide your implementation.

Fewer Bugs: Tests catch errors early, reducing the risk of production issues.

Setting Up a TDD Environment

Node.js: Install Node.js and npm.
Jest: Install Jest using npm (npm install --save-dev jest).

Writing Test Cases with Jest

Use the describe and it functions to define tests.
Test using expect and to be.
Example: it("should add two numbers", () => { expect(2 + 2).toBe(4); });.

Asserting Expected Behavior

Use various Jest matchers to assert expected values, such as:
toBe, toEqual, toBeTruthy, toBeFalsy.

Refactoring and Running Tests

After writing tests, write the implementation code to pass the tests.
Run tests using npm test.
Refactor and repeat to improve code quality.

Mock Functions and Spies

Mock functions allow you to control the behavior of functions during testing.
Spies allow you to track function calls and arguments.

Mocking Libraries and External Dependencies

Mock libraries and dependencies to isolate your code and avoid external dependencies during testing.

Advanced TDD Techniques

BDD (Behavior-Driven Development): Focuses on specifying the desired behavior of the system from a business perspective.
ATDD (Acceptance Test-Driven Development): Drives development based on user stories and acceptance criteria.

Next Up: Debugging JavaScript with Chrome DevTools

In the next session, we'll explore powerful tools in Chrome DevTools to debug your JavaScript code efficiently. Follow us for more insights and tips!