sheet.getData is not a function

I apologize for the confusion. It seems that the `getData` method I mentioned earlier does not exist in SpreadJS. However, you can still retrieve the data from the sheet using different approaches. Here are a few alternatives:

1. Using `getValues` method:

   var sheet = spread.getActiveSheet();
   var data = sheet.getValues();
   console.log(data);

2. Using `getDataSource` method:

   var sheet = spread.getActiveSheet();
   var data = sheet.getDataSource();
   console.log(data);

3. Iterating through cells to retrieve values:

   var sheet = spread.getActiveSheet();
   var data = [];
   var rowCount = sheet.getRowCount();
   var colCount = sheet.getColumnCount();
   
   for (var i = 0; i < rowCount; i++) {
     var row = [];
     for (var j = 0; j < colCount; j++) {
       var cell = sheet.getCell(i, j);
       var cellValue = cell.value();
       row.push(cellValue);
     }
     data.push(row);
   }
   
   console.log(data);

Please try these alternatives and let me know if you encounter any further issues.