найти максимальное число в массиве и его количество повторений

findMaxRepeatValueArray.js

let a = [1,2,3,4,5,6,3,4,6,6,3,7,8,8,8,4,5,7,4,6];

let object = a.reduce( (current, item) => {
  current[item] = (current[item] || 0) + 1;
  return current;
}, {})

let arrayValue = Object.keys(object).reduce( (current, item) => {
  current.push( object[item] );
  return current
}, [])

let maxKey   = Math.max(...Object.keys(object));
let maxValue = Math.max(...arrayValue);

for(let key in object) {
  if(key == maxKey) {
    console.log(`Max value: ${key}, repeat: ${object[key]}`)
  }
  if(object[key] == maxValue) {
    console.log(`Max repeat: ${object[key]}, value: ${key}`)
  }
}

// Max repeat: 4,  value: 4
// Max repeat: 4,  value: 6
// Max value : 8, repeat: 3


uniqueCount =  ["a", "b", "c", "d", "d", "e", "a", "b", "c", "f", "g", "h", "h", "h", "e", "a", "a", "a", "a", "a"];

let objectKeyCountDuplicate = (arr) => arr.reduce((acc, item) => ((acc[item] = (acc[item] || 0) + 1), acc), {});
let getObjectValue = (arr) => Object.keys(arr).reduce((acc, item) => ((acc = acc.concat(arr[item])), acc), [])

var countDupl = objectKeyCountDuplicate(uniqueCount)
/**
 * {
 *   "a": 7, // Max repeat symbol
 *   "b": 2,
 *   "c": 2,
 *   "d": 2,
 *   "e": 2,
 *   "f": 1,
 *   "g": 1,
 *   "h": 3
 * }
 */

let valueDubl = getObjectValue(countDupl); // [7, 2, 2, 2, 2, 1, 1, 3]
objectKeyCountDuplicate(valueDubl)
/**
 * { 
 *   "1": 2,
 *   "2": 4, // 2 Max count dubl list in array
 *   "3": 1,
 *   "7": 1
 * }
 */