Get Equation Text of Chart Trendline with JavaScript via C++

You can retrieve the equation text of a chart trendline using Aspose.Cells for JavaScript via C++. Aspose.Cells provides the DataLabels.text[https://reference.aspose.com/cells/javascript-cpp/datalabels/#text–] property, which returns the equation text of a chart trendline. To use this property, you must first call the Chart.calculate()[https://reference.aspose.com/cells/javascript-cpp/chart/#calculate–] method.

The following screenshot shows the chart with a trendline, and its equation text is shown in red color. We will retrieve this text using the DataLabels.text[https://reference.aspose.com/cells/javascript-cpp/datalabels/#text–] property in the following sample code.

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JavaScript code to get equation text of chart trendline

<!DOCTYPE html>
<html>
    <head>
        <title>Aspose.Cells Example</title>
    </head>
    <body>
        <h1>Read Trendline Equation Example</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 } = 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');
            if (!fileInput.files.length) {
                document.getElementById('result').innerHTML = '<p style="color: red;">Please select an Excel file.</p>';
                return;
            }

            const file = fileInput.files[0];
            const arrayBuffer = await file.arrayBuffer();

            // Instantiating a Workbook object from uploaded file
            const workbook = new Workbook(new Uint8Array(arrayBuffer));

            // Access the first worksheet
            const worksheet = workbook.worksheets.get(0);

            // Access the first chart inside the worksheet
            const chart = worksheet.charts.get(0);

            // Calculate the chart to get the equation text of the trendline
            chart.calculate();

            // Access the trendline
            const trendLine = chart.nSeries.get(0).trendLines.get(0);

            // Read the equation text of the trendline
            const equationText = trendLine.dataLabels.text;

            document.getElementById('result').innerHTML = `<p>Equation Text: ${equationText}</p>`;
        });
    </script>
</html>

Output generated by the sample code

This is the console output of the above sample code.

Equation Text: y = 8.1333x + 5

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