Different Ways to Open Files with Node.js via C++

With Aspose.Cells, it is simple to open files, for example, to retrieve data, or to use a designer template to speed up the development process.

How to Open an Excel File via a Path

Developers can open a Microsoft Excel file using its file path on the local computer by specifying it in the Workbook class constructor. Simply pass the path in the constructor as a string. Aspose.Cells will automatically detect the file format type.

const path = require("path");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "Book1.xlsx");
// Opening through Path
// Creating a Workbook object and opening an Excel file using its file path
const workbook1 = new AsposeCells.Workbook(filePath);
console.log("Workbook opened using path successfully!");

How to Open an Excel File via a Stream

It is also simple to open an Excel file as a stream. To do so, use an overloaded version of the constructor that takes the Stream object that contains the file.

try {
const path = require("path");
const fs = require("fs");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "Book2.xls");
// Opening through Stream
// Create a Stream object
const fstream = fs.createReadStream(filePath);

// Creating a Workbook object, open the file from a Stream object
// That contains the content of file and it should support seeking
const chunks = [];
fstream.on('data', (chunk) => {
chunks.push(chunk);

How to Open a File with Data only

To open a file with data only, use the LoadOptions and LoadFilter classes to set the related attributes and options of the classes for the template file to be loaded.

const path = require("path");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
// Load only specific sheets with data and formulas
// Other objects, items etc. would be discarded

// Instantiate LoadOptions specified by the LoadFormat
const loadOptions = new AsposeCells.LoadOptions(AsposeCells.LoadFormat.Xlsx);

// Set LoadFilter property to load only data & cell formatting
loadOptions.setLoadFilter(new AsposeCells.LoadFilter(AsposeCells.LoadDataFilterOptions.CellData));

// Create a Workbook object and opening the file from its path
const workbook = new AsposeCells.Workbook(path.join(dataDir, "Book1.xlsx"), loadOptions);
console.log("File data imported successfully!");

How to Load Visible Sheets only

While loading a Workbook, sometimes you may only need data in visible worksheets in a workbook. Aspose.Cells allows you to skip data in invisible worksheets while loading a workbook. To do this, create a custom function that inherits the LoadFilter class and pass its instance to LoadOptions.getLoadFilter() property.

const path = require("path");
const AsposeCells = require("aspose.cells.node");

// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const sampleFile = "output.xlsx";
const samplePath = path.join(dataDir, sampleFile);

// Create a sample workbook
// and put some data in first cell of all 3 sheets
const createWorkbook = new AsposeCells.Workbook();
createWorkbook.getWorksheets().get("Sheet1").getCells().get("A1").putValue("Aspose");
createWorkbook.getWorksheets().add("Sheet2").getCells().get("A1").putValue("Aspose");
createWorkbook.getWorksheets().add("Sheet3").getCells().get("A1").putValue("Aspose");
createWorkbook.getWorksheets().get("Sheet3").setIsVisible(false);
createWorkbook.save(samplePath);

// Load the sample workbook
const loadOptions = new AsposeCells.LoadOptions();
loadOptions.setLoadFilter(new AsposeCells.LoadFilter()); // Corrected line by defining LoadFilter properly

const loadWorkbook = new AsposeCells.Workbook(samplePath, loadOptions);
console.log(`Sheet1: A1: ${loadWorkbook.getWorksheets().get("Sheet1").getCells().get("A1").getValue()}`);
console.log(`Sheet1: A2: ${loadWorkbook.getWorksheets().get("Sheet2").getCells().get("A1").getValue()}`);
console.log(`Sheet1: A3: ${loadWorkbook.getWorksheets().get("Sheet3").getCells().get("A1").getValue()}`);

Here is the implementation of the CustomLoad class referenced in the above snippet.

const { Workbook, LoadDataFilterOptions } = require("aspose.cells.node");

class CustomLoad {
startSheet(sheet) {
if (sheet.isVisible()) {
// Load everything from visible worksheet
this.loadDataFilterOptions = LoadDataFilterOptions.All;
} else {
// Load nothing
this.loadDataFilterOptions = LoadDataFilterOptions.Structure;
}
}
}

An exception will be thrown if you try to open non-native Excel files or other file formats (for example PPT/PPTX, DOC/DOCX, etc.) using Aspose.Cells.

There are fair chances that the Workbook constructor may throw OutOfMemoryError while loading large spreadsheets. This exception suggests that the available memory is insufficient to completely load the spreadsheet into memory; therefore, the spreadsheet has to be loaded while enabling the Memory Preferences.

Open Different Microsoft Excel Versions Files with Node.js via C++