Cloud Function failing to parse JSON and write to Cloud Firestore from Webhook

Question

I have a Webhook that POSTs a JSON to my Cloud Function Trigger URL.

I want the Cloud Function to parse the JSON and write it to my Cloud Firestore.

I've tested the Webhook on webhook.site & requestbin.com: they are both receiving the POST request perfectly.

I am guessing that there is some syntax problem somewhere here, around the payload or req.body.

exports.wooCommerceWebhook = async (req, res) => {
    const payload = req.body;

Additionally, this is not an authenticated request, and I deployed the function through the Google Cloud Platform - Cloud Function Console. I did not deploy this through the CLI, or through an application setup with firebase.

index.js

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

exports.wooCommerceWebhook = async (req, res) => {
    const payload = req.body;

    // Write to Firestore - People Collection
    await admin.firestore().collection("people").doc().set({
        people_Email: payload.billing.email,
        people_FirstName: payload.billing.first_name,
        people_LastName: payload.billing.last_name,
    });

    return res.status(200).end();

};

package.json

{
  "name": "sample-http",
  "version": "0.0.1",
  "dependencies": {
      "firebase-admin": "^9.4.2"
  }
}

My Webhook that delivers a POST JSON to my Cloud Function URL:

{
     "billing": {
          "email": "test@test.com",
          "first_name": "First",
          "last_name": "Last"
     }
}

EDIT: I've added

.catch((err) => { console.log(err); })

and now my logs are returning:

Unhandled rejection
TypeError: Cannot read property 'email' of undefined at exports.wooCommerceWebhook (/workspace/index.js:18:43)
at /layers/google.nodejs.functions-framework/functions-framework/node_modules/@google-cloud/functions-framework/build/src/invoker.js:98:17
at processTicksAndRejections (internal/process/task_queues.js:77:11)
Function execution took 599 ms, finished with status: 'crash'
Error detected in test-function-1

Answer 1

I needed to declare each field's data type first.

let billing = "";
let people_Email = "";
let people_FirstName = "";
let people_LastName = "";