TypeScript-NodeJS-Setup

TypeScript and NodeJS: The Proper Setup!

At very first we have to obtain our package.json configurations file with versions, To that,

npm init -y

Then we should create our very first TypeScript File as index.ts at the project root.

Then after that, we should change "main": "index.js", to "main": "index.ts", in the package.json file.

Initialising TypeScript

To initialize TypeScript try,

npx tsc --init

But if you haven't installed TypeScript before then you may encounter an error.

To install TypeScript,

npm install typescript

Then after try again npx tsc --init, it should work now (It is recommended to kill your current terminal and Open a new terminal to avoid any issues)

Coding

Now Let's add a simple code example to index.ts

console.log(123);

const addNumbers = (a: number, b: number) => {
  return a + b;
};

console.log(addNumbers(2, 3));

NodeJS doesn't have the ability to execute TypeScript by default,

So there are 2 main ways to overcome this situation

Method - 01. Compile TypeScript to JavaScript.
Method - 02. TypeScript & NodeJS Dependency.

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Before moving on, let's create a new folder called server and move the index.ts file into it.

$Method - 01:$

Compile TypeScript to JavaScript

As for the Method 01, First, you should create a new folder called dist which stands for distributable at the project root.

Then open tsconfig.json and change "outDir": "./", to "outDir": "./dist", And also make sure to uncomment it.

After that, simply open a new terminal and

tsc

after the line is executed, now you will be able to see an index.js file has been created inside the dist folder & it includes a JavaScript code obtained by compiling from TypeScript at the index.ts file.

Well, sometimes it may be a horrible feeling when you want to run the project each & every time you have to compile it at the terminal by tsc and run.

We can manage that situation by simply updating the package.json file

"scripts": {
    "start": "tsc && node dist/index.js"
},

By using the above "tsc && node dist/index.js", tsc helps to compile the index.ts and (&&) wait for compile then, execute node dist/index.js

Perfect, Now all we have to do is, run and test our TypeScript project setup completely with NodeJS.

npm run start

Output:

$Method - 02:$

TypeScript & NodeJS Dependency installation

By this Method 02, We are able to Directly run TypeScript on NodeJS with the help of a dependency.

For this Method, we have to go through a simple npm installation.

In terminal,

npm i ts-node -D

Here -D at the end of the code line is referred to as install only as a development dependency for the current production (project).

So if you're using this 2nd Method, no need to compile TypeScript, since this ts-node dependency helps us to directly run TypeScript with nodejs instead of converting into JavaScript.

Next, open the package.json file and,

"scripts": {
    "start": "ts-node server/index.ts"    
},

😄 That's it, With this 2nd Method, we can get rid of creating dist directory for compiling purposes and also it helps us to speed up the project development phase by saving the time taken to compile ts as js.

Now Let's run the project

npm run start

Output:

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Personal thought :

I prefer to proceed with the second method but it may vary depending on the situation and how we should apply based on the project scope or the tech stack preferred to use for the project. Thanks & Regards...