console.log("xa")

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')
);

let nums = [1,2,3,1]

var containsDuplicate = function(nums) {
    let obj = {};
    for(let i =0; i< nums.length; i++){
        if(obj[nums[i]]){
            obj[nums[i]] += 1;
            return true;
        }else{
            obj[nums[i]] = 1;
        }
    }
    return false;
};

console.log(containsDuplicate(nums));

const toFixed = (n, fixed) => ~~(Math.pow(10, fixed) * n) / Math.pow(10, fixed);
// Examples
toFixed(25.198726354, 1);       // 25.1
toFixed(25.198726354, 2);       // 25.19
toFixed(25.198726354, 3);       // 25.198
toFixed(25.198726354, 4);       // 25.1987
toFixed(25.198726354, 5);       // 25.19872
toFixed(25.198726354, 6);       // 25.198726

// promisify(f, true) to get array of results
function promisify(f, manyArgs = false) {
  return function (...args) {
    return new Promise((resolve, reject) => {
      function callback(err, ...results) { // our custom callback for f
        if (err) {
          reject(err);
        } else {
          // resolve with all callback results if manyArgs is specified
          resolve(manyArgs ? results : results[0]);
        }
      }

      args.push(callback);

      f.call(this, ...args);
    });
  };
}

// usage:
f = promisify(f, true);
f(...).then(arrayOfResults => ..., err => ...);

arr = [] // empty array
const isEmpty = arr => !Array.isArray(arr) || arr.length === 0;

// Examples
isEmpty([]); // true
isEmpty([1, 2, 3]); // false