Direct calculation of custom function without writing it in a worksheet with JavaScript 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.” by ourselves and 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 in a code that we have not written our custom function anywhere in a worksheet and it is calculated directly by our own custom logic.
Programming Sample
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Custom Function Example</title>
</head>
<body>
<h1>Implement Direct Calculation Of Custom Function</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, AbstractCalculationEngine, CalculationOptions } = AsposeCells;
AsposeCells.onReady({
license: "/lic/aspose.cells.enc",
fontPath: "/fonts/",
fontList: [
"arial.ttf",
"NotoSansSC-Regular.ttf"
]
}).then(() => {
console.log("Aspose.Cells initialized");
});
class CustomEngine extends AbstractCalculationEngine {
// Override the calculate method with custom logic
calculate(data) {
// Check the formula name and calculate it yourself
if (data.functionName === "MyCompany.CustomFunction") {
// This is our calculated value
data.calculatedValue = "Aspose.Cells.";
}
}
}
document.getElementById('runExample').addEventListener('click', async () => {
const fileInput = document.getElementById('fileInput');
let workbook;
if (fileInput.files.length) {
const file = fileInput.files[0];
const arrayBuffer = await file.arrayBuffer();
workbook = new Workbook(new Uint8Array(arrayBuffer));
} else {
// Create a new workbook if no file is provided
workbook = new Workbook();
}
// Access first worksheet
const ws = workbook.worksheets.get(0);
// Add some text in cell A1
ws.cells.get("A1").putValue("Welcome to ");
// Create a calculation options with custom engine
const opts = new CalculationOptions();
opts.customEngine = 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);
// Write the returned value into B1 for demonstration
ws.cells.get("B1").putValue(ret);
// Prepare download of the modified workbook
const outputData = workbook.save(SaveFormat.Xlsx);
const blob = new Blob([outputData]);
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'output.xlsx';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download Excel File';
document.getElementById('result').innerHTML = '<p style="color: green;">Calculated Value: ' + ret + '</p>';
});
</script>
</html>
Console Output
Below is the console output of the above sample code.
Calculated Value: Welcome to Aspose.Cells.