Using for in to iterate through objects values and return the highest value

I am trying to return the mode of a passed array. I have read a lot about for in loops but due to es6 syntax used in these examples, I am struggling to understand how I can use this loop. My question: I want to return the key that has the highest value of all the object pairs.

I.e with the following object:

{ '4': 1, '6': 1, '7': 1, '8': 1, '10': 2, '12': 3 }

I want to return the key that contains the highest value. In this case it would be 12 since 3 is the highest value out of the pairs.

Is it possible to use a for in loop in a similar way to how I would iterate through an array to find the highest value. (I understand that non-array objects are not indexed in the same way arrays are, but I need to compare one key:value pair to the next in the loop and not sure how to code that). I.e:

let highest = 0;
      for(const x in count){
        if(count[x 1] > count[x]){
         highest = count[x][i 1];
       }

When I pass the code below it returns 0 so I assume the For In loop isn't working as expected.

Full Code for reference:

function highestRank(arr){
  
  const count = {};
  
  for(let i=0; i<arr.length; i  ){
    if(count.hasOwnProperty(arr[i]) === false){
        count[arr[i]]= 1;
      }else{
        count[arr[i]]  = 1;
      }
  }
 //code below is the issue
  let highest = 0;
  for(const x in count){
    if(count[x 1] > count[x]){
     highest = count[x][i 1];
   }
  } 
  
  return highest;
}

CodePudding user response：

Traditional loop version, use variables greatest and its respective key, loop the object properties

const count = { '4': 1, '6': 1, '7': 1, '8': 1, '10': 2, '12': 3 };

let greatest = -Infinity;
let key;
for (let x in count) {
  if (count[x] > greatest) {
    key = x;
    greatest = count[key];
  }
}

console.log(key, greatest);

CodePudding user response：

You can use Object.entries combined with reduce and in cumulator keep object with maxKey and maxValue;

const data = { '4': 1, '6': 1, '7': 1, '8': 1, '10': 2, '12': 3 };
const max = Object.entries(data).reduce(({maxKey, maxValue = -Infinity}, [key, value]) => {
  if(value > maxValue){
    maxValue = value;
    maxKey = key;
  }
  return {maxKey, maxValue}
}, {});

console.log(max);