Merge Files with JavaScript via C++

Introduction

Aspose.Cells provides different ways for merging files. For simple files with data, formatting, and formulas, the Workbook.combine(Workbook) method can be used to combine several workbooks, and the Worksheet.copy(Worksheet) method can be used to copy worksheets into a new workbook. These methods are easy to use and effective, but if you have a lot of files to merge, you might find that they take a lot of system resources. To avoid this, use the **CellsHelper.mergeFiles(string[], string, string)** static method, a more efficient way to merge several files.

Merge Files Using Aspose.Cells for JavaScript via C++

The following sample code illustrates how to merge large files using the **CellsHelper.mergeFiles(string[], string, string)** method. It takes two simple but large files, Book1.xls and Book2.xls. The files contain formatted data and formulas only.

<!DOCTYPE html>
<html>
    <head>
        <title>Aspose.Cells Example</title>
    </head>
    <body>
        <h1>Merge Excel Files and Rename Sheets Example</h1>
        <input type="file" id="fileInput" accept=".xls,.xlsx" multiple />
        <button id="runExample">Merge and Rename Sheets</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, CellsHelper } = 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');
            resultDiv.innerHTML = '';

            if (!fileInput.files.length || fileInput.files.length < 2) {
                resultDiv.innerHTML = '<p style="color: red;">Please select at least two Excel files to merge.</p>';
                return;
            }

            // Read selected files into Uint8Array array
            const files = [];
            for (let i = 0; i < fileInput.files.length; i++) {
                const file = fileInput.files[i];
                const arrayBuffer = await file.arrayBuffer();
                files.push(new Uint8Array(arrayBuffer));
            }

            // Create cacheFile name and destination name (virtual in browser)
            const cacheFile = "test.txt";
            const dest = "output.xlsx";

            // Call CellsHelper.mergeFiles with file byte arrays, cacheFile name and destination name
            // Note: In the browser environment mergeFiles is expected to accept file byte arrays and return merged file bytes.
            const mergedData = CellsHelper.mergeFiles(files, cacheFile, dest);

            // Log cacheFile as in original code
            console.log(cacheFile);

            // Load the merged workbook from returned bytes
            const workbook = new Workbook(new Uint8Array(mergedData));

            // Rename sheets sequentially starting at 1
            let i = 1;
            const worksheets = workbook.worksheets;
            for (let j = 0; j < worksheets.count; j++) {
                worksheets.get(j).name = `Sheet1${i}`;
                i++;
            }

            // Save the modified workbook and prepare download link
            const outputData = workbook.save(SaveFormat.Xlsx);
            const blob = new Blob([outputData], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" });
            const downloadLink = document.getElementById('downloadLink');
            downloadLink.href = URL.createObjectURL(blob);
            downloadLink.download = 'output.xlsx';
            downloadLink.style.display = 'block';
            downloadLink.textContent = 'Download Merged and Renamed Excel File';

            resultDiv.innerHTML = '<p style="color: green;">Files merged and sheets renamed successfully! Click the download link to get the modified file.</p>';
        });
    </script>
</html>
Combine Multiple Worksheets into a Single Worksheet with JavaScript via C++