云 Function Firebase request.body 未定义

Question

User side: POST method using fetch function:

let response = await fetch(url, {
  "method": "POST",
  "headers": {
    "Content-Type": "application/json"
  },
  "body": JSON.stringify({"stripeToken": token.id})
});

Server side: URL to fetch is a Firebase Cloud Function:

const functions = require('firebase-functions');
const cors = require('cors')({origin: true});
const stripe = require("stripe")("PRIVATE_KEY");

exports.chargeStripe = functions.https.onRequest( async (request, response) => {

    // Getting token
    let token = request.body.stripeToken;

    // Creating charge
    let charge = await stripe.charges.create({
        amount: 99,
        currency: 'eur',
        description: 'Payment',
        source: token
    });

    // Sending response
    charge ? send(response, 200, {message: 'Success'}) : send(response, 500, {message: 'Error!'});

});

The problem is that I am getting console.log(token) → 'undefined' .

Update 1

It seems that Chrome (browser) is blocking the fetch function (CORS policy). If I test the end-point via Insomnia, everything is working fine.

So, someone knows what to do in this case?

Update 2

Thanks to Doug Stevenson , I added CORS middleware inside the function:

exports.chargeStripe = functions.https.onRequest( (request, response) => {

    // Enable CORS using the `cors` express middleware.
    return cors(request, response, async () => {

        // Reading token
        let token = request.body.stripeToken;

        // Charging user
        let charge = await stripe.charges.create({
            amount: 99,
            currency: 'eur',
            description: 'Payment',
            source: token
        });

        // Sending response 
        response.status(200).send('Ok');
    });

}); 

Now everything works!

Answer 1

Thanks to Doug Stevenson , I added the cors package :

const cors = require('cors')({origin: true});

And then, I used CORS middleware inside the function. So, the final solution is:

const functions = require('firebase-functions');
const cors = require('cors')({origin: true});
const stripe = require("stripe")("PRIVATE_KEY");

exports.chargeStripe = functions.https.onRequest( (request, response) => {

    // Enable CORS using the `cors` express middleware.
    return cors(request, response, async () => {

        // Reading token
        let token = request.body.stripeToken;

        // Charging user
        let charge = await stripe.charges.create({
            amount: 99,
            currency: 'eur',
            description: 'Payment',
            source: token
        });

        // Sending response 
        response.status(200).send('Ok');
    });

});