BUG FIX: Some spreadsheet files report fully empty rows as undefined rather than [] for some reason (#120)

Author: alaric-rd

lib/importer/backend.js

@@ -255,12 +255,14 @@ function getMergedRows(sheet, start, end) {
   for(let index = start; index <= end; index++) {
     result.push(getMergedRow(data, merges, index));
   }
+
   return result;
 }
 
 // Given a row, return the columns from start to end.
 // This will extract the desired column range, padding with "undefined"s if the row ends too soon.
 function extractColsFromRow(row, start, end) {
+  if(row === undefined) return [];
   // Slice row; but this may result in fewer elements than we want if the row
   // wasn't that long to begin with
   const sliced = row.slice(start, end);