Direct calculation of custom function without writing it in a worksheet with JavaScript via C++
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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 use a custom function named MyCompany.CustomFunction() and calculate its value as "Aspose.Cells." ourselves. This value is then automatically concatenated with the value of cell A1, which is "Welcome to ", by the calculation engine, and the final calculated result is "Welcome to Aspose.Cells.". As you can see, we have not written our custom function in any worksheet; it is calculated directly by our 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
// the 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.