Detecting Empty Worksheets with JavaScript via C++
Check for Populated Cells
Worksheets can have one or more cells populated with values where a value can be simple (text, numeric, date/time) or a formula or a formula-based value. In such a case, it is easy to detect if a given worksheet is empty or not. All we have to check is the Cells.maxDataRow or Cells.maxDataColumn properties. If the aforementioned properties return zero or positive values that means, one or more cells have been populated; however, if any of these properties return -1, that indicates that none of the cells have been populated in the given worksheet.
Check for Empty Initialized Cells
All cells that have values are automatically initialized; however, there is a possibility that a worksheet has cells with only formatting applied. In such a scenario, the Cells.maxDataRow or Cells.maxDataColumn properties will return -1 indicating the absence of any populated values, but initialized cells due to cell formatting cannot be detected using this approach. In order to check if a worksheet has empty initialized cells, it is advised to use the Enumerator.MoveNext method on the enumerator acquired from Cells collection. If the Enumerator.MoveNext method returns true, that means there are one or more initialized cells in the given worksheet.
Check for Shapes
It is possible that a given worksheet does not have any populated cells; however, it could contain shapes & objects such as controls, charts, images, and so on. If we need to check if a worksheet contains any shape, we can do it by inspecting the ShapeCollection.count property. Any positive value indicates the presence of shape(s) in the worksheet.
Programming Sample
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Example</title>
</head>
<body>
<h1>Check Non-Empty Worksheets Example</h1>
<input type="file" id="fileInput" accept=".xls,.xlsx,.csv" />
<button id="runExample">Run Example</button>
<a id="downloadLink" style="display: none;">Download Result</a>
<div id="result"></div>
</body>
<script src="aspose.cells.js.min.js"></script>
<script type="text/javascript">
const { Workbook, SaveFormat, Worksheet, Cell, Utils } = AsposeCells;
AsposeCells.onReady({
license: "/lic/aspose.cells.enc",
fontPath: "/fonts/",
fontList: [
"arial.ttf",
"NotoSansSC-Regular.ttf"
]
}).then(() => {
console.log("Aspose.Cells initialized");
});
document.getElementById('runExample').addEventListener('click', async () => {
const fileInput = document.getElementById('fileInput');
const resultDiv = document.getElementById('result');
if (!fileInput.files.length) {
resultDiv.innerHTML = '<p style="color: red;">Please select an Excel file.</p>';
return;
}
const file = fileInput.files[0];
const arrayBuffer = await file.arrayBuffer();
// Instantiating a Workbook object from the uploaded file
const book = new Workbook(new Uint8Array(arrayBuffer));
const messages = [];
// Loop over all worksheets in the workbook
for (let i = 0; i < book.worksheets.count; i++) {
const sheet = book.worksheets.get(i);
// Check if worksheet has populated cells
if (sheet.cells.maxDataRow !== -1) {
messages.push(`${sheet.name} is not empty because one or more cells are populated`);
}
// Check if worksheet has shapes
else if (sheet.shapes.count > 0) {
messages.push(`${sheet.name} is not empty because there are one or more shapes`);
}
// Check if worksheet has empty initialized cells
else {
const range = sheet.cells.maxDisplayRange;
const rangeIterator = range.getEnumerator();
if (rangeIterator.moveNext()) {
messages.push(`${sheet.name} is not empty because one or more cells are initialized`);
}
}
}
if (messages.length) {
resultDiv.innerHTML = '<ul>' + messages.map(m => `<li>${m}</li>`).join('') + '</ul>';
} else {
resultDiv.innerHTML = '<p style="color: green;">No non-empty worksheets found.</p>';
}
});
</script>
</html>