jwt-simple-error-identify

Easy use of jwt, based on the jwt-simple module, but you can identify the type of error ocurred, if is the case. Important, this module gives you the same functionality that the jwt-simple module, but extended. With jwt-simple-error-identify you can know the error type, so in your code, you can check it with the 'instance of' operator. If you do not need that, use jwt-simple instead.

Install

$ npm install --save jwt-simple-error-identify

Usage

const jwt = require('jwt-simple-error-identify').jwt;
const ExpiredToken = require('jwt-simple-error-identify').ExpiredToken; //the error
const InvalidAlgorithm = require('jwt-simple-error-identify').InvalidAlgorithm; //the error

//Or you can do that
/*
*	const JWT = require(jwt-require-error-identify);
*	const jwt = JWT.jwt;
*	const ExpiredToken = JWT.ExpiredToken
*	//and so on with all type of errors.
*
*/

var payload = {
	foo: 'bar',
	exp: moment().unix() //The module recognize the exp params and use it as the expiration time, 
						//so do not use it for another purpose.
						// I use moment for the example you can use whatever you want.
					   //Using moment().unix(), the token is expired after creation so we will catch the ExpiredToken error.
}
const secret = 'xxx';

//encode
const token = jwt.encode(payload, secret);

// decode
try{
	const decoded = jwt.decode(token, secret);
	console.log(decoded); //=> { foo: 'bar' }
	//In this case that won't shown because the decode will throw an ExpiredToken error.
}catch(err){
	if(err instanceof ExpiredToken){
		//do something, for example if you are using oauth you can use the refresh token to obtain a new access token.
		console.log('Token Expired');
	}
	if(err instanceof InvalidAlgorithm){
		//do something, for example you can try with other algorithm.
		console.log('Invalid Algorithm');
	}
}

Error types

InvalidToken, InvalidAlgorithm, ExpiredToken, SignatureError.

The most general errors are InvalidToken and InvalidAlgorithm. Exist also ExpiredToken and SignatureError, that inherit from InvalidToken.

Note that if you use ExpiredToken or SignatureError in the catch, you also need to check the InvalidToken because it could be thrown in cases that ExpiredToken and SignatureError not.

encode params

/*
*	jwt.encode(payload, secret, algorithm)
*/

NOTE: algorithm is optional.

decode params

/*
 * jwt.decode(token, key, noVerify, algorithm)
 */

// decode, by default the signature of the token is verified
var decoded = jwt.decode(token, secret);
console.log(decoded); //=> { foo: 'bar' }

// decode without verify the signature of the token,
// be sure to KNOW WHAT ARE YOU DOING because not verify the signature
// means you can't be sure that someone hasn't modified the token payload
var decoded = jwt.decode(token, secret, true);
console.log(decoded); //=> { foo: 'bar' }

// decode with a specific algorithm (not using the algorithm described in the token payload)
var decoded = jwt.decode(token, secret, false, 'HS256');
console.log(decoded); //=> { foo: 'bar' }

Algorithms

By default the algorithm to encode is HS256.

The supported algorithms for encoding and decoding are HS256, HS384, HS512 and RS256.

// encode using HS512
jwt.encode(payload, secret, 'HS512')