Roman Numeral converter solution optimization

My request to freeCodeCamp to check the complexity of my code. highly optimized solution.

function convertToRoman(num) {
  let result = "";

  const arabicNum = [
    ["M", 1000],
    ["CM", 900],
    ["D", 500],
    ["CD", 400],
    ["C", 100],
    ["XC", 90],
    ["L", 50],
    ["XL", 40],
    ["X", 10],
    ["IX", 9],
    ["V", 5],
    ["IV", 4],
    ["I", 1],
  ];
  let n = arabicNum.length;
  //reversing an array
  for (let i = 0; i < n / 2; i++) {
    let temp = arabicNum[i];
    arabicNum[i] = arabicNum[n - 1 - i];
    arabicNum[n - i - 1] = temp;
  }

  let low = 0;
  let high = arabicNum.length - 1;

  while (num >= 0) {
    low = 0; //initializing each time because it gets changed inside binary Search

    // binarySearch
    while (low <= high) {
      let mid = Math.floor((low + high) / 2);

      if (num > arabicNum[mid][1]) low = mid + 1;
      else if (num < arabicNum[mid][1]) high = mid - 1;
      else {
        result += arabicNum[mid][0];
        //as num gets equal to arabicNum[mid][1] it return from the function
        return result;
      }
    }
    result += arabicNum[high][0];
    num = num - arabicNum[high][1];
  }
}

convertToRoman(1006);

I’m not sure I understand why you need a ‘binary search’?