get most occurring elements in array JavaScript

Question

I have an array that I want to get the most occurring elements,

First scenario

let arr1 = [\'foo\', \'foo\', \'foo\', \         


        

Answer 1

You can calculate the max for each of the values and only return those which match via grouping them with an Array.reduce:

const mostFrequent = data => data.reduce((r,c,i,a) => {
  r[c] = (r[c] || 0) + 1
  r.max = r[c] > r.max ? r[c] : r.max
  if(i == a.length-1) {
    r = Object.entries(r).filter(([k,v]) => v == r.max && k != 'max')
    return r.map(x => x[0])
  }
  return r
}, {max: 0})

console.log(mostFrequent(['foo', 'foo', 'foo', 'bar', 'bar', 'bar', 'baz', 'baz']))
console.log(mostFrequent(['foo', 'foo', 'foo', 'bar', 'baz']))