@astronautlabs/jwt

An isomorphic JWT library (works in browser and Node.js)

Usage no npm install needed!

<script type="module">
  import astronautlabsJwt from 'https://cdn.skypack.dev/@astronautlabs/jwt';
</script>

README

@/jwt

This library is Alpha quality in the 0.0.x series (no automatic updates by semver). Please take caution if you choose to use it, and do not use it in production. We welcome PRs for fixes, features and general improvements.

A simple isomorphic JWT library (works in browser and Node.js) with support for signing and verifying JWTs using a number of common algorithms.

Installation

npm install @astronautlabs/jwt

Usage

Common Options

  • now -- Specify the UNIX wall clock time to use when enforcing exp claims. When not specified, Date.now() is used.
  • algorithm -- The signature algorithm to use. See Supported Algorithms for the options.
  • secretOrKey -- The key to use for the operation. When using asymmetric algorithms (like RS256, ES256, etc) you should pass public keys for validate() and private keys for encode()

Signing

    async encode(claims: any, options: EncodeOptions): Promise<Token>

Remarks

Returns a Token object with the given claims, and signed by the credentials specified in options (see algorithm and secretOrKey).

Example

import { JWT } from '@astronautlabs/jwt';

try {
    let token = await JWT.encode({ sub: 123 }, { algorithm: 'HS256', secretOrKey: 'stuff' });
    console.dir(token); // => { string: 'eY...', claims: { sub: ..., ... } }
} catch (e) {
    console.error('Failed to validate token: ');
    console.error(e);
}

Validation

JWT.validate(string : string, options: DecodeOptions): Promise<Token>

Returns a Token object if the given string is a valid (and trusted) JWT. If validation fails, throws an Error.

Types of errors JWT.validate() can throw:

  • Algorithm mismatch: If the token header's alg claim does not match the configured algorithm (options.algorithm)
  • Signature mismatch: If the signature does not match
  • Expiration: If the token's exp claim is not acceptable according to policy
import { JWT } from '@astronautlabs/jwt';

try {
    let token = await JWT.validate(`eY...`, { algorithm: 'HS256', secretOrKey: 'stuff' });
    console.dir(token); // => { string: 'eY...', claims: { sub: ..., ... } }
} catch (e) {
    console.error('Failed to validate token: ');
    console.error(e);
}

Expiration

You can configure a policy for built-in validation of the exp claim when validating tokens. To do so, specify { validate: { exp: "(policyName)" }} within the options passed to JWT.validate().

The available policies are:

  • when-present (default) -- When a token has an exp claim, fail validation if the token is expired
  • force -- Require tokens to have a valid (fresh) exp claim
  • ignore -- Ignore exp even when it is present (it will still be available on token.claims).

You can override the current time by providing options.now. Consider using this instead of options.validate.exp = 'ignore'.

Options

  • validate
    • exp -- Expiration policy. For more see Expiration

Supported Platforms

  • Browser/Web using WebCrypto
  • Node.js

Supported Algorithms

  • HS256
  • HS384
  • HS512
  • RS256
  • RS512
  • ES256