TypeScript

• Strongly typed language
• A superset of JavaScript i.e. any valid JavaScript is valid TypeScript
• Adds time to development but makes debugging and refactoring much easier in the long run
• Extension for typescript file is .ts
• It can be added to a project using npm install --save-dev typescript

let name: string = "Kush" // valid
let age: int = "20" // error

type objType = {
	name: string,
	age: int,
	location: string,
}

let myObject: objType = {
	name: "Kush Gabani",
	age: 20,
	location: "Surat"
}

Jest

• Unit Testing for javascript
• Run test suites, individual test cases
• Provides a variety of methods for unit testing
• An extension of a test file is .test.js
• To add jest to a project, we run the following command npm install --save-dev jest
• To run test cases, we need to add a test script in package.json

"scripts": [
	"test": "jest",
];

• The syntax to write a Test case

test("test case description", () => {
	// ...test case
});

Functions for asserting

• toBe()