为什么“RangeError：无效状态代码：0”，firebase 函数

Question

With the following functions called as http request:

exports.newID = functions.https.onRequest(async (req, res) => {
  let citiesRef = fireStore.collection('system').doc('uid_counter');
  let snapshot = await citiesRef.get();
  let counter = snapshot.get('counter');
  console.log('current counter = ', counter);
  res.status(200).send(counter);

The firebase functions console.log indicate that counter can be gotten well, but response gets an error:

I have no idea why I've gotten "RangeError: Invalid status code: 0" despite I've specified status(200) . Thank you for your suggestions.

Answer 1

The Express documentation for res.send([body]) states that

The body parameter can be a Buffer object, a String, an object, or an Array.

So sending a Number is most probably the cause of your problem.

You could send the counter value as an object, as follows:

res.status(200).send({ counter: counter});