Difficulties with posting data to Google Firebase HTTP Functions - node.js

Question

I am trying to POST some variables as part of req.body to a Firebase Cloud Function. I am using the modern fetch() syntax as following:
const { licenseCode } = this.state;
fetch('https://myAPI.com/inputLicense', {
method: 'POST',
headers: {
"Content-Type": "application/json"
},
body: JSON.stringify({ licenseCode })
})
And here is how my Cloud function looks:
exports.inputLicense = functions.https.onRequest((request, response) => {
// const { licenseCode } = request.body
console.log(request.get('content-type'))
console.log('query', request.query)
console.log('body', request.body)
})
Unfortunately, all of the above logging produces empty objects or undefined in the case of the first line. In a usual Express setup, I know I need to use:
app.use(bodyParser.json()); // for parsing application/json
app.use(bodyParser.urlencoded({ extended: true })); // for parsing application/x-www-form-urlencoded
But don't know how to do it with cloud functions. Google claims in their Docs they parse my requests automatically, based on the header but I just can't get it to work.
Any help is more then welcome, thanks in advance.

Answer 1

It seems like you solved the problem, but for anyone else having a problem. In my case the problem was the firebase cloud function triggering on the cors preflight request which contains no body.
I solved it by removing the application/json content-type in the fetch call and decoding the json body manually in the cloud function
// on the client
fetch(functionURL + '/' + name, {
body: JSON.stringify({abc: 123}),
method: 'POST',
mode: 'cors',
})
// on the server
functions.https.onRequest(async (req, res) => {
const {abc} = JSON.parse(req.body)
res.set('content-type', 'application/json')
res.set('Access-Control-Allow-Origin', '*')
res.status(200)
res.send({result: abc})
})

Answer 2

I've done some tests and apparently the problem comes from the object destructuring.
The following should work:
const obj = { licenseCode: this.state };
fetch('https://myAPI.com/inputLicense', {
method: 'POST',
headers: {
"Content-Type": "application/json"
},
body: JSON.stringify(obj)
})