fix bug when loading empty cell multiple times

Author: theoephraim

lib/GoogleSpreadsheetCell.js

@@ -5,7 +5,7 @@ const { columnToLetter } = require('./utils');
 const { GoogleSpreadsheetFormulaError } = require('./errors');
 
 class GoogleSpreadsheetCell {
-  constructor(parentSheet, rowIndex, columnIndex, cellData = {}) {
+  constructor(parentSheet, rowIndex, columnIndex, cellData) {
     this._sheet = parentSheet; // the parent GoogleSpreadsheetWorksheet instance
     this._row = rowIndex;
     this._column = columnIndex;
@@ -14,7 +14,8 @@ class GoogleSpreadsheetCell {
     return this;
   }
 
-  _updateRawData(newData) {
+  // newData can be undefined/null if the cell is totally empty and unformatted
+  _updateRawData(newData = {}) {
     this._rawData = newData;
     this._draftData = {}; // stuff to save
     this._error = null;

test/cells.test.js

@@ -73,6 +73,13 @@ describe('Cell-based operations', () => {
       expect(() => { sheet.getCellByA1('A1'); }).toThrow();
     });
 
+    it('can load a cell multiple times (this was a bug)', async () => {
+      await sheet.loadCells('J10');
+      expect(sheet.getCellByA1('J10').value).toBeNull();
+      await sheet.loadCells('J10');
+      expect(sheet.getCellByA1('J10').value).toBeNull();
+    });
+
     describe('invalid filters', () => {
       _.each({
         'invalid A1 range': 'NOT-A-RANGE',