feat: add prefilling pdf form fields via api

packages/lib/server-only/pdf/insert-form-values-in-pdf.ts

@@ -0,0 +1,54 @@
+import { PDFCheckBox, PDFDocument, PDFDropdown, PDFRadioGroup, PDFTextField } from 'pdf-lib';
+
+export type InsertFormValuesInPdfOptions = {
+  pdf: Buffer;
+  formValues: Record<string, string | boolean | number>;
+};
+
+export const insertFormValuesInPdf = async ({ pdf, formValues }: InsertFormValuesInPdfOptions) => {
+  const doc = await PDFDocument.load(pdf);
+
+  const form = doc.getForm();
+
+  if (!form) {
+    return pdf;
+  }
+
+  for (const [key, value] of Object.entries(formValues)) {
+    try {
+      const field = form.getField(key);
+
+      if (!field) {
+        continue;
+      }
+
+      if (typeof value === 'boolean' && field instanceof PDFCheckBox) {
+        if (value) {
+          field.check();
+        } else {
+          field.uncheck();
+        }
+      }
+
+      if (field instanceof PDFTextField) {
+        field.setText(value.toString());
+      }
+
+      if (field instanceof PDFDropdown) {
+        field.select(value.toString());
+      }
+
+      if (field instanceof PDFRadioGroup) {
+        field.select(value.toString());
+      }
+    } catch (err) {
+      if (err instanceof Error) {
+        console.error(`Error setting value for field ${key}: ${err.message}`);
+      } else {
+        console.error(`Error setting value for field ${key}`);
+      }
+    }
+  }
+
+  return await doc.save().then((buf) => Buffer.from(buf));
+};