Typescript Basic Configurations: Understand tsconfig.json basics.

Typescript Basic Configurations: Set up a simple TypeScript project and understand tsconfig.json basics.

Set up a simple TypeScript project and understand tsconfig.json basics.

1. Install TypeScript

First, ensure you have Node.js and npm installed. Then, install TypeScript globally:

npm install -g typescript

Alternatively, for a specific project, install TypeScript locally in the project folder:

npm install --save-dev typescript

2. Initialize a New Project

Create a new directory for your project, navigate into it, and initialize a tsconfig.json file:

mkdir my-typescript-project
cd my-typescript-project
tsc --init

3. Understanding tsconfig.json

The tsconfig.json file is the configuration file for TypeScript. It controls how TypeScript compiles .ts files. Here's a breakdown of some of the key options:

Essential tsconfig.json Options

compilerOptions: This section controls the TypeScript compiler's settings.
- target: Specifies the JavaScript version TypeScript should output. Common values are:
```
"target": "ES5" // Transpiles to ECMAScript 5 (widely supported)
"target": "ES6" // ECMAScript 2015
```
- module: Determines the module system for output files. Common values:
```
"module": "commonjs" // For Node.js projects
"module": "es6" // For frontend (modern browsers)
```
- outDir: Specifies the output directory for compiled JavaScript files.
```
"outDir": "./dist"
```
- rootDir: Sets the root directory for TypeScript files.
```
"rootDir": "./src"
```
- strict: Enables strict type-checking options, ensuring safer code.
```
"strict": true
```
- esModuleInterop: Enables compatibility between CommonJS and ES6 modules.
```
"esModuleInterop": true
```
include and exclude:
- include: Specifies files/directories to be included in the project.
- exclude: Excludes files/directories from compilation.
Example:
```
"include": ["src/**/*"],
"exclude": ["node_modules", "dist"]
```

4. Sample tsconfig.json

Here’s a minimal tsconfig.json setup:

{
  "compilerOptions": {
    "target": "ES6",
    "module": "commonjs",
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true,
    "esModuleInterop": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist"]
}

5. Create a Simple TypeScript File

Inside the src directory, create an index.ts file:

// src/index.ts
const greet = (name: string): string => `Hello, ${name}!`;
console.log(greet("World"));

6. Compile and Run

To compile your TypeScript code, run:

tsc

This generates JavaScript files in the dist folder (as per outDir in tsconfig.json). To execute the compiled JavaScript file:

node dist/index.js

7. Additional Configuration Options

As you expand, you may explore other options like:

allowJs: Allows JavaScript files to be compiled.
sourceMap: Generates .map files, helpful for debugging.

Typescript Type Inference

Typescript Union & Intersection Types