casl react

import { AbilityBuilder } from '@casl/ability';
import React, { useState, useContext } from 'react';
import { AbilityContext } from './Can';

function updateAbility(ability, user) {
  const { can, rules } = new AbilityBuilder();

  if (user.role === 'admin') {
    can('manage', 'all');
  } else {
    can('read', 'all');
  }

  ability.update(rules);
}

export default () => {
  const [username, setUsername] = useState('');
  const [password, setPassword] = useState('');
  const ability = useContext(AbilityContext);
  const login = () => {
    const params = {
      method: 'POST',
      body: JSON.stringify({ username, password })
    };
    return fetch('path/to/api/login', params)
      .then(response => response.json())
      .then(({ user }) => updateAbility(ability, user));
  };

  return (
    <form>
      {/* input fields */}
      <button onClick={login}>Login</button>
    </form>
  );
};