Find the second largest number in array

Find the second largest number in array

Write a function named getSecondLargest. This function has one parameter: an array of  numbers. The function must find and return the second largest number in.

Sample input 

`
nums = [2,3,6,6,5]
getSecondLargest(nums)
`

Sample output

`5`

Solution 1 - bad

/**
*   Return the second largest number in the array.
*   @param {Number[]} nums - An array of numbers.
*   @return {Number} The second largest number in the array.
**/

// In 34 years old man's mind 

function getSecondLargest(nums) {
    let largestNum = findLargestNum(nums);
    let filteredArr = nums.filter(num => num !== largestNum);
    return findLargestNum(filteredArr);
}

function findLargestNum(nums) {
    let largestNum = nums[0];
    for (let i = 0; i < nums.length; i++) {
        if (largestNum < nums[i + 1]) {
            largestNum = nums[i + 1];
        }
    }
    return largestNum;
}

Solution 2 - better

// Using Math.max built-in function

function getSecondLargest(nums) {
    const max = Math.max(...nums)
    
    return Math.max(...nums.filter(x => x !== max))
}

Solution 3 - best

// Using only one for loop

function getSecondLargest(nums) {
  let first = nums[0]; 
  let second = -1;

  for (let i = 0; i < nums.length; i++) {
    if (nums[i] > first) {
       second = first;
       first = nums[i];
    }

    if (nums[i] > second && nums[i] < first) {
       second = nums[i];
    }
  }
  
  return second;
}