Find the second most frequent element in array JavaScript

We are required to write a JavaScript function that takes in a string and returns the character from the string that appears for the second most number of times.

Example

The code for this will be −

const arr = [5, 2, 6, 7, 54, 3, 2, 2, 5, 6, 7, 5, 3, 5, 3, 4];
const secondMostFrequent = arr => {
   const map = arr.reduce((acc, val) => {
      if(acc.has(val)){
         acc.set(val, acc.get(val) + 1);
      }else{
         acc.set(val, 1);
      };
      return acc;
   }, new Map);
   const frequencyArray = Array.from(map);
   return frequencyArray.sort((a, b) => {
      return b[1] - a[1];
   })[1][0];
};
console.log(secondMostFrequent(arr));

Output

The output in the console −

2