function Welcome(props) {
  return <h1>Hello, {props.name}</h1>;
}

function App() {
  return (
    <div>
      <Welcome name="Sara" />
      <Welcome name="Cahal" />
      <Welcome name="Edite" />
    </div>
  );
}

ReactDOM.render(
  <App />,
  document.getElementById('root')
);

const hammingDistance = (num1, num2) =>
  ((num1 ^ num2).toString(2).match(/1/g) || '').length;
  
hammingDistance(2, 3); // 1

new StringBuilder(hi).reverse().toString()

const primes = num => {
  let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2),
    sqroot = Math.floor(Math.sqrt(num)),
    numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2);
  numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y === x)));
  return arr;
};

primes(10); // [2, 3, 5, 7]

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var containsDuplicate = function(nums) {
    return new Set(nums).size !== nums.length
};

const jwt = require("jsonwebtoken");

const authToken = (req, res, next) => {
	const token = req.headers["x-auth-token"];

	try {
	req.user = jwt.verify(token, process.env.ACCESS_TOKEN_SECRET);

	next();
	} catch (err) {
	console.log(err.message);
	res.status(401).json({ msg: "Error authenticating token" });
	}
};

module.exports = authToken;