JSON comes in undefined, where is the data lost? - node.js

Question

I am using postman to test a rest API I'm building for a project. I'm trying to send some data to a post method, but the data is getting lost somewhere between Postman and the endpoint.
I've tried tracing the data with console logs, but nothing comes out (req.body is undefined). I'm pretty sure the issue isn't with the endpoint or router, as the same error comes up in postman as in the console of my IDE, which means there's some sort of communication.
// json I'm putting into postman. validated with Jsonlint.com
{
"Name": "testN",
"file": "file1",
"Path": "/home/userf",
"userName": "user1"
}
// profileWrite.js
const dbProfileWrite = require('../...db-ProfileWrite');
const bodyParser = require('body-parser');
var app = express();
app.use(bodyParser.json());
// my post method
async function post(req, res, next) {
try {
console.log("attempting to parse data: " + req.body);
let profile = req.body;
console.log("data parsed, writing profiles");
profile= await dbProfileWrite.writeProfile(profile);
res.status(201).json(profile);
} catch (err) {
next(err);
}
}
module.exports.post = post;
UPDATE 7/15/19:I have recreated a microversion of my project that is having this issue on stackblitz. there's some sort of package error that I'm working on, but here's the link. I've recreated the methodology I'm using in my project with the router and all and looked at the example in the express docs. hopefully this helps isolate the issue.The data still comes in undefined when I post to this api through postman, so helpfully this much smaller view of the whole project helps.

Answer 1

Assuming you are using Express framework, by the look of the post function. You need to use a middlewear function to process request body using body-parser. Make sure you are using the correct parser in this case
app.use(bodyParser.json())

Answer 2

You don't need body-parser anymore it was put back in to the core of express in the form of express.json, simply use app.use(express.json()).
To access the body of your request use req.body, it should come with a object with the keys representing the json sent;
var app = express();
app.use(express.json());
async function post(req, res, next) {
try {
console.log("attempting to parse data: " + req.body);
let profile = req.body; // no need to use any functions to parse it
console.log("data parsed, writing profiles");
profile= await dbProfileWrite.writeProfile(profile);
res.status(201).json(profile);
console.log("profilecreated");
} catch (err) {
next(err);
}
}
See the express documentation

Answer 3

Solved the issue myself with a little help from John Schmitz. The issue was that I was defining the router and the server before actually telling it how to handle json bodies/ objects, so the body came through as the default undefined. In my index.js, the following is what fixed the code:
app.use(express.urlencoded({ extended: true }));
app.use(express.json());
app.use('/api/v1', router);
the key to this is that the app is told to use json and express.urlencoded before the router is declared. these actions have to happen in this order, and all before app.listen is called. once the app is listening, all of its params are set and you can't change them. Tl;dr: node is VERY picky, and you HAVE to define these things in the right place. thanks all for the help.