Looping on GeoJSON to get maximum/minimum altitude

I need to create to create 2 function to return max and min Z/elevation/altitude values from LineString GeoJSON file.

i have created 2 function to get that before, but i was using MultiLineString GeoJSON file, but now i am using LineString.

this one of the 2 function:

    function minHPoint(arr, multi) {
  var min = Infinity, len, tmpArr, minPoint;
  if (multi) {
    multiLen = arr.length;
    }
  else {
    tmpArr = arr;
    multiLen = 0;
  };
  while (multiLen--) {

    if (multiLen >= 0) tmpArr = arr[multiLen];
    len = tmpArr.length;
    while (len--) {
      if (tmpArr[len][2] < min) {
        min = tmpArr[len][2];
        minPoint = tmpArr[len];
      }
    }
  }
  return minPoint;

};

var coords = layer.feature.geometry.coordinates;
var minPoint = minHPoint(coords, (layer.feature.geometry.type == 'MultiLineString'));
minH = minPoint[2];
$('#Low-Point').html("Low point: "+Math.round(minH)+" Meters");