How to perform calculations on specific fields in a PDF form using an ONLYOFFICE macro

ONLYOFFICE macros are powerful and versatile, making them useful not only for automating tasks in documents, spreadsheets, and presentations but also in PDF forms. In this blog post, we’ll show you how to create and run a unique macro that performs calculations on specific fields within a form. In this example, the macro helps to calculate taxes, making the process faster and more accurate.

Building the macro

Retrieving all the forms from the document

First we retrieve all the fields from the document:

// Get all forms from the document
    const document = Api.GetDocument();
    let forms = document.GetAllForms();

• Api.GetDocument() gets the active document.
• GetAllForms() retrieves all form fields in the document

Defining form keys

Then, we define the form keys:

  // Formkeys of input forms
    var formkey1 = "Form1";
    var formkey2 = "Form2";
    var taxFormkey = "TaxForm";

    // Formkeys of result forms
    var sumResultKey = "SumResult";
    var taxResultKey = "TaxResult";

• formkey1, formkey2, and taxFormkey store the identifiers of the input fields.
• sumResultKey and taxResultKey store the identifiers of the output fields where the results will be inserted.

Retrieving form values

The getFormValue function iterates through forms to find a form matching formKey:

  // Function to get the value of a form by its key
    function getFormValue(formKey) {
        for (let form of forms) {
            if (form.GetFormKey() === formKey) {
                return parseFloat(form.GetText()) || 0;
            }
        }
    }

• GetText() retrieves the text value of the form.
• parseFloat() converts the text to a number.

If conversion fails, it defaults to 0 to prevent errors in calculations.

Inserting values into forms

The setFormValue function searches for a form field matching formKey. The SetText() method updates the field with a formatted numeric value (2 decimal places).

  // Function to set the value of a result form
    function setFormValue(formKey, value) {
        for (let form of forms) {
            if (form.GetFormKey() === formKey) {
                form.SetText(value.toFixed(2));
            }
        }
    }

Main calculation

Inside the main calculation function we:

• Retrieve user input values from form fields.
• Compute the sum of input1 and input2.
• Calculate tax as a percentage of the sum.
• Call setFormValue() to insert results into their respective fields.

 // Main calculation function
    function calculateAndInsert() {
        let input1 = getFormValue(formkey1);
        let input2 = getFormValue(formkey2);
        let taxInput = getFormValue(taxFormkey);
        // Perform calculations
        var sum = parseFloat(input1) + parseFloat(input2);
        var tax = sum * taxInput / 100; // % tax

        // Insert results
        setFormValue(sumResultKey, sum);
        setFormValue(taxResultKey, tax);
    }

The entire macro code is the following:

(function () {
    // Get all forms from the document
    const document = Api.GetDocument();
    let forms = document.GetAllForms();
    // Formkeys of input forms
    var formkey1 = "Form1";
    var formkey2 = "Form2";
    var taxFormkey = "TaxForm";

    // Formkeys of result forms
    var sumResultKey = "SumResult";
    var taxResultKey = "TaxResult";

    // Function to get the value of a form by its key
    function getFormValue(formKey) {
        for (let form of forms) {
            if (form.GetFormKey() === formKey) {
                return parseFloat(form.GetText()) || 0;
            }
        }
    }

    // Function to set the value of a result form
    function setFormValue(formKey, value) {
        for (let form of forms) {
            if (form.GetFormKey() === formKey) {
                form.SetText(value.toFixed(2));
            }
        }
    }

    // Main calculation function
    function calculateAndInsert() {
        let input1 = getFormValue(formkey1);
        let input2 = getFormValue(formkey2);
        let taxInput = getFormValue(taxFormkey);
        // Perform calculations
        var sum = parseFloat(input1) + parseFloat(input2);
        var tax = sum * taxInput / 100; // % tax

        // Insert results
        setFormValue(sumResultKey, sum);
        setFormValue(taxResultKey, tax);
    }

    // Call the calculation function
    calculateAndInsert();
})();

Now, let’s run the macro and see how it works!

At ONLYOFFICE, we strive to provide users with versatile tools tailored to their needs. Macros are powerful additions to your toolkit, and we hope this one becomes a valuable asset for you.

We also encourage you to explore our extensive library of API methods and create your own macros. If you have macros or ideas to share, feel free to reach out – we’re always open to suggestions and collaboration. Best of luck in your exploratory endeavors!