Kyun

This project is still in the development stage and may have breaking changes in the patch version.

Goal: A little bit faster and type-safe permission rules for TS/JS.

Installation

pnpm add kyun

Quick Start

import { kyun } from 'kyun';

type User = { id: string; role: 'admin' | 'user' };
type Post = { id: string; ownerId: string; status: 'draft' | 'published' };

// Authentication Context
const k = kyun.$for<User>();

const postRules = k.define<Post>(({ c, u, s }) => {
  // Admins can do anything
  c.allow('read').if(c.eq(u.role, 'admin'));
  
  // Users can read published posts or their own drafts
  c.allow('read').if(
    c.or(
      c.eq(s.status, 'published'),
      c.eq(s.ownerId, u.id)
    )
  );
  
  // Only owners can edit
  c.allow('update').if(c.eq(s.ownerId, u.id));
});

const rules = {
  posts: postRules
};
const instance = k.use(rules);

const user = { id: 'user-1', role: 'user' };
const post = { id: 'post-1', ownerId: 'user-1', status: 'draft' };

// authorize
const can = instance.for(user);

if (can.posts.read(post)) {
  console.log('User can read this post');
}

if (can.posts.update(post)) {
  console.log('User can update this post');
}

// Server side
type Rules = typeof rules;
const packed = instance.pack(user);
// Transfer `packed` to the client via props or global state

// Client side
import { kyunClient } from 'kyun';

const can = kyunClient<Rules>({ rules: packed });

if (can.posts.read(post)) {
  // Works instantly on the client!
}

Get rules from Better Auth

import { kyunPlugin } from 'kyun/better-auth';

const auth = betterAuth({
  plugins: [
    kyunPlugin({
      rules,
    }),
  ]
});

// client
const client = createAuthClient({
  plugins: [
    kyunClientPlugin()
  ]
});

const packed = await client.kyun.getRules(); //
const can = kyunClient<Rules>({ rules: packed.rules });

if (can.posts.update(todo)) {
  console.log('User can update this todo');
}

License

MIT