code: function calculateBoundsFromNestedArrayOfArrays (array) {
      var x1 = null, x2 = null, y1 = null, y2 = null;
  
      for (var i = 0; i < array.length; i++) {
        var inner = array[i];
  
        for (var j = 0; j < inner.length; j++) {
          var innerinner = inner[j];
          for (var k = 0; k < innerinner.length; k++) {
            var lonlat = innerinner[k];
  
            var lon = lonlat[0];
            var lat = lonlat[1];
  
            if (x1 === null) {
              x1 = lon;
            } else if (lon < x1) {
              x1 = lon;
            }
  
            if (x2 === null) {
              x2 = lon;
            } else if (lon > x2) {
              x2 = lon;
            }
  
            if (y1 === null) {
              y1 = lat;
            } else if (lat < y1) {
              y1 = lat;
            }
  
            if (y2 === null) {
              y2 = lat;
            } else if (lat > y2) {
              y2 = lat;
            }
          }
        }
      }
  
      return [x1, y1, x2, y2];
    }
docs: /*
  Internal: Calculate a bounding box from an array of arrays of arrays
  [
  [ [lng, lat],[lng, lat],[lng, lat] ]
  [ [lng, lat],[lng, lat],[lng, lat] ]
  [ [lng, lat],[lng, lat],[lng, lat] ]
  ]