Common interview coding questions

Frequency-counter

//Common algorithm to calculate frequency of each character or number in an array

function frequencyCounter(arr) {
  let result = {};

  arr.forEach((i) => {
    if (result[i]) {
      result[i]++;
    } else {
      result[i] = 1;
    }
  });

  //arr.forEach((i) => result[i] ? result[i]++ : result[i]=1); //one liner

  console.log(result);
}