The problem:
input is a list of ranges
[[2,4],[4,5],[4,5]]

output - all possible numbers by concatinating numbers from ranges
244, 245, ..., 344

to be clear:
Input:
A list of ranges, where each range is represented as a 2-element array [start, end] (inclusive).
Example: [[2, 4], [4, 5], [4, 5]]

Output:
An array of strings. Each string represents a number formed by picking one digit from each range in the given order.
Example Output for above input:
["244", "245", "254", "255", "344", "345", "354", "355", "444", "445", "454", "455"]



The solution I wrote:
const findNumbers = (ranges) =>{
  let rangeLength = ranges.length;
    
  const buildCombination(arr, r, path){
    let res = []
    if(r === rangeLength){
      res.push(path)
      return res
    }

    for(let i=arr[0]; i<= arr[arr.length-1]; i++){
      path = ${path}${i}
      buildCombination(ranges[r+1], r+1, path)
     
    }
  }
  
  return buildCombination(ranges[0], 0, '')
  
}