fix bug

google-script.js

@@ -26,31 +26,33 @@ function doPost(e) {
     
     var headers = [];
     
-    // 2. If sheet is brand new (no rows), create headers first
+    // 2. Determine headers
     if (sheet.getLastRow() === 0) {
-      // Extract keys from data, excluding 'sheetName' which is a control parameter
-      headers = Object.keys(data).filter(function(key) {
-        return key !== "sheetName";
-      });
+      // Use provided headers if available
+      if (data.headers && Array.isArray(data.headers)) {
+        headers = data.headers;
+      } else {
+        // Fallback: Use keys but exclude internal control keys
+        headers = Object.keys(data).filter(function(key) {
+          return !["sheetName", "headers"].includes(key);
+        });
+      }
       sheet.appendRow(headers);
     } else {
-      // 3. If sheet already exists, get existing headers from the first row
+      // Get existing headers from the first row
       var lastCol = sheet.getLastColumn();
       if (lastCol > 0) {
         headers = sheet.getRange(1, 1, 1, lastCol).getValues()[0];
-      } else {
-        // Fallback for edge cases where lastRow > 0 but lastCol is 0
-        headers = Object.keys(data).filter(function(key) {
-          return key !== "sheetName";
-        });
-        sheet.appendRow(headers);
       }
     }
     
-    // 4. Map data to the determined headers
+    // 3. Map data to headers
     var row = headers.map(function(header) {
-      // data[header] might be undefined for some rows if schema changes
-      return data[header] !== undefined ? data[header] : "N/A";
+      var val = data[header];
+      if (val === undefined || val === null) return "N/A";
+      // If value is an object or array, stringify it to avoid [Ljava.lang.Object]
+      if (typeof val === 'object') return JSON.stringify(val);
+      return val;
     });
     
     sheet.appendRow(row);