firebase云函数ServerValue增量不起作用

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();

exports.incrementField = functions.https.onCall(async (data, context) => {
  const { documentPath, fieldName, increment } = data;

  try {
    const documentRef = admin.firestore().doc(documentPath);
    const documentSnapshot = await documentRef.get();
    const currentValue = documentSnapshot.get(fieldName);

    if (typeof currentValue === 'number') {
      const newValue = currentValue + increment;
      await documentRef.update({ [fieldName]: newValue });
      return { success: true, message: 'Field incremented successfully.' };
    } else {
      return { success: false, message: 'Field is not a number.' };
    }
  } catch (error) {
    console.error('Error incrementing field:', error);
    return { success: false, message: 'An error occurred while incrementing field.' };
  }
});