Guided: Configure and Structure a TypeScript Library with Modules - Geometry Helper Part 1

Welcome to Guided: Configure and Structure a TypeScript Library with Modules - Geometry Helper Part 1.

This is the first lab in a 2-lab series in which you will be implementing a library for performing geometric calculations using Typescript.

The project you have been given is a standard Node project. You will need to create and configure TypeScript settings using a tsconfig.json file before implementing the library using TypeScript paradigms.

Lastly, you will be exporting and importing your library to be used within the main application. If you are stuck at any time, feel free to take a look at the solution directory.

info> Important Note: The application will throw errors when run until you complete the lab, wherein it should work correctly.

How to Start the Application

The application can be started by clicking the Run button in the Terminal or by running the command npm start in the Terminal.

First, you will need to setup a TypeScript configuration.

This is done by creating a tsconfig.json file. This file will contain two key properties:

• compilerOptions which are settings for how TypeScript files will be compiled
• include which will dictate which files/directories should be compiled

Now, you can start your implementation for some geometry calculations.

In the SquareShape.ts file there is a SquareShape class defined. It has the export keyword which allows it to be used in other files, mainly index.ts and by extension, the main application.

Your task here is to calculate values such as area, perimeter, volume, and surface area for squares and cubes.

Next, do the same calculations for round shapes.

In the RoundShape.ts file there is a RoundShape class defined. Like SquareShape, it also has the export keyword.

You will be implementing the same functions here, but for circles and spheres.

By prefixing the RoundShape and SquareShape classes with export, you can now import them in other files with a statement like import { RoundShape } from "./RoundShape".

In this application context, importing two classes isn't that big of a deal. However, in a larger project you might have many more classes to use and having to copy the same import statements across multiple files and modules can become a hassle.

This is where index.ts comes in. The src/index.ts file can be used to trivialize this by having all the import statements for your library classes in index and then re-exporting them using an export statement. This allows you to only need a single import statement in other files and modules where you can select the classes you need straight from index. Now that the library classes are implemented and correctly exported/imported into the main application, you can run the application to see the results.

Running the application will print out four lines to the Terminal showing the geometric calculations for each shape with a specified value.

A circle with radius 7 has an area of 153.93804002589985 and a circumference of 43.982297150257104 
    
A sphere with a radius of 7 has a volume of 1436.7550402417319 and a surface area of 615.7521601035994

A square with length 5 has an area of 25 and a circumference of 20 
  
A cube with a radius of 5 has a volume of 125 and a surface area of 150