exceljs · alubbe · Jun 19, 2020 · Jun 19, 2020
diff --git a/lib/utils/shared-strings.js b/lib/utils/shared-strings.js
@@ -2,7 +2,7 @@ class SharedStrings {
   constructor() {
     this._values = [];
     this._totalRefs = 0;
-    this._hash = {};
+    this._hash = Object.create(null);
   }
 
   get count() {

diff --git a/spec/integration/issues/issue-1339-speciel-cell-file.spec.js b/spec/integration/issues/issue-1339-speciel-cell-file.spec.js
@@ -0,0 +1,43 @@
+const ExcelJS = verquire('exceljs');
+
+// this file to contain integration tests created from github issues
+const TEST_XLSX_FILE_NAME = './spec/out/wb.test.xlsx';
+
+describe('github issues', () => {
+  it('issue 1339 - Special cell value results invalid file', async () => {
+    const wb = new ExcelJS.stream.xlsx.WorkbookWriter({
+      filename: TEST_XLSX_FILE_NAME,
+      useStyles: true,
+      useSharedStrings: true,
+    });
+    const ws = wb.addWorksheet('Sheet1');
+    const specialValues = [
+      'constructor',
+      'hasOwnProperty',
+      'isPrototypeOf',
+      'propertyIsEnumerable',
+      'toLocaleString',
+      'toString',
+      'valueOf',
+      '__defineGetter__',
+      '__defineSetter__',
+      '__lookupGetter__',
+      '__lookupSetter__',
+      '__proto__',
+    ];
+    for (let i = 0, len = specialValues.length; i < len; i++) {
+      const value = specialValues[i];
+      ws.addRow([value]);
+      ws.getCell(`B${i + 1}`).value = value;
+    }
+    await wb.commit();
+    const wb2 = new ExcelJS.Workbook();
+    await wb2.xlsx.readFile(TEST_XLSX_FILE_NAME);
+    const ws2 = wb2.getWorksheet('Sheet1');
+    for (let i = 0, len = specialValues.length; i < len; i++) {
+      const value = specialValues[i];
+      expect(ws2.getCell(`A${i + 1}`).value).to.equal(value);
+      expect(ws2.getCell(`B${i + 1}`).value).to.equal(value);
+    }
+  });
+});