TypeScript Configuration

⚙️ TypeScript Configuration (tsconfig.json)

TypeScript Configuration is done using a file called tsconfig.json.

This file tells the TypeScript compiler how to compile your code and which rules to follow.

📄 What is tsconfig.json?

• A JSON file placed at the root of your project

• Controls:

  • Target JavaScript version

  • Strictness rules

  • Module system

  • Output folders

  • Type checking behavior

📌 Presence of tsconfig.json = this folder is a TypeScript project

🛠️ Create tsconfig.json

Run this command in your project folder:

This generates a default config file.

🧩 Basic tsconfig.json Example

🔑 Important compilerOptions (Most Used)

1️⃣ target

Defines JavaScript version output.

Common values:

• ES5 (old browsers)

• ES6 / ES2015

• ES2020

• ESNext

2️⃣ module

Defines module system.

Options:

• commonjs → Node.js

• esnext → Modern bundlers

• amd, umd

3️⃣ rootDir

Where your TypeScript source files live.

4️⃣ outDir

Where compiled JavaScript files go.

5️⃣ strict ⭐ (Highly Recommended)

Enables all strict type-checking options.

Includes:

• strictNullChecks

• noImplicitAny

• strictFunctionTypes

• strictBindCallApply

6️⃣ noImplicitAny

Disallows implicit any.

❌

7️⃣ strictNullChecks

Forces explicit handling of null & undefined.

8️⃣ esModuleInterop

Improves compatibility with CommonJS modules.

Used when importing libraries like Express.

9️⃣ forceConsistentCasingInFileNames

Avoids issues on case-sensitive systems.

🔟 skipLibCheck

Skips checking .d.ts files (faster builds).

📁 Include & Exclude Files

Include

Exclude

🧪 Example: Real-World Recommended Config

▶️ Compile Using Config

(TypeScript automatically reads tsconfig.json)

🔑 tsconfig.json Summary

⭐ Best Practices

✔ Always use strict: true
✔ Separate src and dist
✔ Use skipLibCheck for faster builds
✔ Commit tsconfig.json to version control