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Femi Abimbola
Femi Abimbola

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Setting up Express with Typescript, Prettier and Eslint in post-2026

#typescript #node #backend #express

Hi

So you want to setup express with Typescript in the right way in post 2026 right? Let me show you how!

Before setting up, ensure you have Node.js installed. Version 20+ or later is highly recommended.

To check if you have Node.js installed. Type the command in your terminal

node --version
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You should see something similar to this

v22.20.0
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Step 1: Initialize the Project

Let's create the project directory and initialize the project

mkdir express-typescript-project   //This create the project directory
cd express-typescript-project      // This enter the project directory
npm init -y  //This create package.json with the default setting
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Step 2: Install Express dependencies

Install express and its corresponding dev dependencies

npm install express    //This install express as dependencies
npm install -D typescript @types/node @types/express
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Step 3: Install typescript run time

tsx is significantly faster, requires zero configuration for ESM

npm install --save-dev tsx
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Step 4: Configure TypeScript

Generate a tsconfig.json file to configure the TypeScript compiler

npx tsc --init
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Open tsconfig.json and replace it with this

{
  "compilerOptions": {
    "target": "ESNext",
    "module": "NodeNext",
    "moduleResolution": "NodeNext",
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true, 
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "sourceMap": true, // Helpful for debugging
    "resolveJsonModule": true, // Let's you import .json files
    "noImplicitReturns": true, // Forces better logic flow
    "noFallthroughCasesInSwitch": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist"]
}
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Step 5: Create the index File

Create a src directory and add an index.ts file inside it:

mkdir src // This create the source folder
touch src/index.ts  //Create the index.ts
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In the index.ts file, write the following code

import express, { Request, Response } from 'express';

const app = express();
const port = process.env.PORT || 8000;

app.get('/', (req: Request, res: Response) => {
  res.send('Hello, TypeScript + Express!');
});

app.listen(port, () => {
  console.log(`Server running at http://localhost:${port}`);
});
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Step 6: Update the Scripts in your package.json file is updated 

  "scripts": {
    "dev": "tsx watch src/index.ts",
    "build": "tsc",
    "start": "node dist/server.js",
    "start:prod": "npm run build && npm run start",
    "lint": "eslint .",
    "lint:fix": "eslint . --fix",
    "format": "prettier --write \"**/*.{ts,js,json,md,yml,yaml}\""
  },
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Ensure your package.json has the type module

 "type": "module",
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  • build: Compiles TypeScript to JavaScript in the dist folder.
  • start: Runs the compiled JavaScript.
  • dev: Runs in development mode with auto-reloading.
  • lint:fix Fixes the linting issues

Step 7: Run the Application

For development: npm run dev
For production: First build with npm run build, then npm start

Visit http://localhost:8000 in your browser to see the "Hello, TypeScript + Express!" message.

Top comments (1)

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sleewoo profile image
Slee Woo •

Great start!
Next step is adding some automation like here - kosmojs.dev/start.html

KosmoJS taking care about every aspect - type safety, runtime validation based on your types, fetch clients etc.
You only add routes by creating files.