TypeScript Configuration

Let's configure the code in Modules and Packages for JS to work with TypeScript

At the moment, the directory structure for the root file fourier, is as below

            $ ls *
main.js         package.json

hello:
hello.js
$
          

The code files are as below, in the file hello.js in the folder hello in root, fourier:

const os = require('os')

// create anonymous function and bind to variable SayArch
const SayArch = () => {
  let arch = "OS info: \n"
  arch += `Type ${os.type()} ` +
            `Release: ${os.release()} ` +
            `Platform: ${os.platform()}`
  return arch
}

module.exports = { SayArch }

In the root file, main.js in the root folder, fourier:

'use strict';

const { SayArch } = require('./hello/hello.js')

console.log("Hello World")
let arch = SayArch()
console.log(arch)

The package.json, which acts as the versioning for the third-party packages, in its current state, exists as below:

            {
"name": "fourier",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
    "start": "node main.js",
    "test": "echo \"Error: no test specified\" && exit 1"
},
"keywords": [],
"author": "",
"license": "ISC"
}
          

So, let's download the packages needed for node for TypeScript
And initialize the config file for TypeScript, tsconfig.json
Note: Any package can be searched from npm.js, npmjs.com and installed using the syntax npm install PACKAGE

siliconSavanna@Fourier-PC

npm install typescript ts-node @types/node|

The resulting execution for the terminal becomes:

siliconSavanna@Fourier-PC

            $ npm install typescript ts-node @types/node

added 19 packages, and audited 20 packages in 39s

found 0 vulnerabilities
$ ls
hello                   node_modules            package.json
main.js                 package-lock.json
$ npx tsc --init

Created a new tsconfig.json with:                                                  
                                                                                TS 
target: es2016
module: commonjs
strict: true
esModuleInterop: true
skipLibCheck: true
forceConsistentCasingInFileNames: true


You can learn more at https://aka.ms/tsconfig
$
          

The final part of the configuration is to rename all js files to ts. With this done. There's a final change on the start script of package.json. Let ts-node from the local project module run the program. By local I mean prefixing npx

            ...
"scripts": {
    "start": "npx ts-node main.ts",
    "test": "echo \"Error: no test specified\" && exit 1"
},
...
          

Note: I'm going to omit listing files in node_modules directory
Thus, the directory structure for the project with TypeScript configured becomes:

            $ find . -not -path "./node_modules/*" 
.
./main.ts
./node_modules
./package-lock.json
./package.json
./tsconfig.json
./hello
./hello/hello.ts
$
          

The codebase for main.ts becomes

'use strict';

const { SayArch } = require('./hello/hello.ts')

console.log("Hello World")
let arch = SayArch("OS Info ==> ")
console.log(arch)

And the codebase for ./hello/hello.ts becomes

const os = require('os')

const SayArch = (header: string):string => {
  let arch = header
  arch += `Type ${os.type()} ` +
            `Release: ${os.release()} ` +
            `Platform: ${os.platform()}`
  return arch
}

export { SayArch }

Now, finally onto running the project that has been created and configured in TypeScript

            $ npm start 

> fourier@1.0.0 start
> npx ts-node main.ts

Hello World
OS Info ==> Type Darwin Release: 21.6.0 Platform: darwin
$
          

That's it. We're done!