# @lokesh-kaushik/jwt-auth

Encode, decode, and validate JSON Web Tokens (JWTs) with ease.

This library provides simple and efficient methods for working with JWTs in both JavaScript and TypeScript projects.

## Features

- Encode (create) JWT tokens
- Decode JWT tokens
- Validate JWT tokens

## Installation

You can install the package via npm:

```bash
npm install @lokesh-kaushik/jwt-auth
```

Or with yarn:

```bash
yarn add @lokesh-kaushik/jwt-auth
```

## Usage

First, import the methods you need:

```js
import { encode_jwt, decode_jwt, validate_jwt } from "@lokesh-kaushik/jwt-auth";
```

### Methods

#### 1. `encode_jwt`

Creates a JWT token.

Arguments:

- `secret` (string, required): The secret key used to sign/encode the JWT.
- `id` (string | number, required): An identifier (user ID, etc.) to include in the payload.
- `payload` (object, required): The payload data you want to encode.
- `ttl` (number, optional): Time to live in seconds. If provided, the token will have an expiration time.

Returns: A signed JWT token as a string.

Example:

```javascript
const secret = "your-secret-key";
const id = "user123";
const payload = { role: "admin", name: "John Doe" };
const token = encode_jwt(secret, id, payload, 3600);
console.log(token);
```

#### 2. `decode_jwt`

Decodes a JWT token, verifies its signature & returns the encoded data and expiration date (if `ttl` was passed while encoding).

Arguments:

- `secret` (string, required): The same secret key used to encode the JWT signature.
- `jwt` (string, required): The JWT token to decode.

Returns: An object containing the `id`, `payload`, and `expires_at` (as a Date or null).

Example:

```javascript
const secret = "your-secret-key";
const token = "your-jwt-token";
try {
  const decoded = decode_jwt(secret, token);
  console.log(decoded);
} catch (error) {
  console.error(error.message);
}
```

#### 3. `validate_jwt`

Validates a JWT token by decoding it and checking the signature.

Arguments:

- `secret` (string, required): The same secret key used to encode the JWT signature.
- `jwt` (string, required): The JWT token to validate.

Returns: A boolean indicating whether the JWT is valid.

Example:

```javascript
const secret = "your-secret-key";
const token = "your-jwt-token";
const isValid = validate_jwt(secret, token);
console.log(isValid); // true or false
```

### Author -Lokesh Kaushik

[GitHub](https://github.com/c0dewithLokesh/)

[LinkedIn](https://www.linkedin.com/in/lokesh--kaushik/)