Ritesh Kumar

Posted on Jun 27, 2022

How To Make A Typescript + NodeJS Express Project with eslint, EJS and Restart On Typescript Server Changes

#typescript #node #webdev #tutorial

Start with a clean project

pnpm init
or
npm init -y

Install some dependencies

pnpm add -save-dev eslint @types/node @types/express typescript ts-node-dev
pnpm add --save express ejs 

or 

npm install -save-dev eslint @types/node @types/express typescript ts-node-dev
npm install --save express ejs

make a new folder for your project

mkdir src
touch src/app.ts

src/app.ts

import express from 'express';
const app = express();
const port = 3000;
app.use(express.json());
app.use(express.static("public"));
app.set("view engine", "ejs");

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(port, () => {
  return console.log(`http://localhost:${port}`);
});

create a new folder for your public folder

create a new folder of views

Create tsconfig.json

{
    "compilerOptions": {
        "module": "commonjs",
        "esModuleInterop": true,
        "target": "es6",
        "moduleResolution": "node",
        "sourceMap": true,
        "outDir": "dist"
    },
    "lib": [
        "es2015"
    ]
}

Now we will run eslint’s initialization command to interactively set up the project:

npx eslint --init

Now You have to answer some questions to finish the initialization process:

How would you like to use ESLint?: To check syntax and find problems
What type of modules does your project use?: JavaScript modules (import/export)
Which framework does your project use?: None of these
Does your project use TypeScript?: Yes
Where does your code run?: Node
What format do you want your config file to be in?: JavaScript

Finally, you will be prompted to install some additioanl eslint libraries. Choose Yes. The process will finish and you’ll be left with the following configuration file:

Now we will use ts-node-dev for watching the changes in our typescript server file

As we already installed the dev dependency we do not have to do much we just have to add the start script in our package.json file

Lets Change our package.json and add some lines

add main

"main": "dist/app.js",

add lint and start in scripts

"lint": "eslint . --ext .ts",
"start": "ts-node-dev src/app.ts"

Finally It should look like this

{
  "name": "typescript-node",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "lint": "eslint . --ext .ts",
    "start": "ts-node-dev src/app.ts"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@types/express": "^4.17.13",
    "@types/node": "^18.0.0",
    "@typescript-eslint/eslint-plugin": "^5.30.0",
    "@typescript-eslint/parser": "^5.30.0",
    "eslint": "^8.18.0",
    "ts-node-dev": "^2.0.0",
    "typescript": "^4.7.4"
  },
  "dependencies": {
    "ejs": "^3.1.8",
    "express": "^4.18.1"
  }
}

Now start the project with pnpm or npm

pnpm start
or
npm start

Hurray you have a new project! 🎉

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Stateful vs Stateless Architecture

Top comments (10)

Jakob Attkinson • Jun 28 '22

Here are a couple of nooby questions:

should ts-node-dev watch the app.ts or the start command should look like this: "start": "npx tsc && ts-node-dev dist/src/app.js ?

Meaning, should we be watching the ts file or the compiled version?

If you deploy this app on production, how would you start the server?

Ritesh Kumar • Jun 28 '22 • Edited

no there is no need to add tsc in start script ts-node-dev do all the jobs but in production we should use our transpiled file as we have already type checked everything

Jakob Attkinson • Jun 28 '22

ts-node-dev doesn't transpile, does it? At least in my case, if I want to have the dist/build folder, I do need to manually run tsc

Ritesh Kumar • Jun 28 '22

No, actually It does not transpile it automatically I will recommend you to create different scripts for development and production
"start:dev": "ts-node-dev src/app.ts", "start": "tsc && node dist/app.js"

Jakob Attkinson • Jun 28 '22

Thank you!

Rense Bakker • Jun 28 '22

For a typescript project highly prefer ts-node-dev over nodemon
With your current start script, if you make a change to the typescript code it will not recompile automatically, you can fix that with nodemon, but ts-node-dev has no need to recompile your code, it will just serve the changed typescript immediately which is obviously much faster.

Rense Bakker • Jun 28 '22

Actually I just noticed you're doing stuff double... because you are using ts-node in your nodemon config you dont need to tsc before running nodemon. ts-node is also much slower than ts-node-dev though and you dont need to have nodemon at all, you can just add a script like this: "start": "ts-node-dev src/app.ts" and thats all you need.