Direct calculation of custom function without writing it in a worksheet with Node.js via C++

Direct calculation of custom function without writing it in a worksheet

This topic explains how you can directly calculate your custom functions without first writing them in a worksheet. Please use the Worksheet.calculateFormula(formula, opts) method for this purpose.

Please see the following sample code that illustrates the usage of this method. We have used a custom function named MyCompany.CustomFunction() and we calculate its value as "Aspose.Cells." ourselves; then this value is automatically concatenated with the value of cell A1, which is "Welcome to ", by the calculation engine, and the final calculated value returns as "Welcome to Aspose.Cells.". As you can see, we have not written our custom function anywhere in a worksheet, and it is calculated directly by our own custom logic.

Programming Sample

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

class CustomEngine extends AsposeCells.AbstractCalculationEngine {
// Override the Calculate method with custom logic
calculate(data) {
// Check the formula name and calculate it yourself
if (data.getFunctionName() === "MyCompany.CustomFunction") {
// This is our calculated value
data.setCalculatedValue("Aspose.Cells.");
}
}
}

class ImplementDirectCalculationOfCustomFunction {
static run() {
// Create a workbook
const wb = new AsposeCells.Workbook();

// Access first worksheet
const ws = wb.getWorksheets().get(0);

// Add some text in cell A1
ws.getCells().get("A1").putValue("Welcome to ");

// Create a calculation options with custom engine
const opts = new AsposeCells.CalculationOptions();
opts.setCustomEngine(new CustomEngine());

// This line shows how you can call your own custom function without
// a need to write it in any worksheet cell
// After the execution of this line, it will return
// Welcome to Aspose.Cells.
const ret = ws.calculateFormula("=A1 & MyCompany.CustomFunction()", opts);

// Print the calculated value
console.log("Calculated Value: " + ret);
}
}

// Example invocation
ImplementDirectCalculationOfCustomFunction.run();

Console Output

Below is the console output of the above sample code.

Calculated Value: Welcome to Aspose.Cells.

Related Article

Implement Custom Calculation Engine to extend the Default Calculation Engine of Aspose.Cells