loging response from server does not work - mongodb

Question

I am following a tutorial from Coding Garden. There he writes to a database and sends it then back to the client.
When I try to do it, I do not get a respond from the server. I guess there has been a mix up in my code.
When I go to localhost/5000/posts there is no database. Why do I not get an errormessage, or a database?
Best regards
Expected Result:
https://youtu.be/JnEH9tYLxLk?t=3060
client code
const form = document.querySelector('form');
const loadingElement = document.querySelector(".loading");
const API_URL = "http://localhost:5000/posts";
loadingElement.style.display = "none";
form.addEventListener('submit', (event) => {
event.preventDefault();
const formData = new FormData(form);
const name = formData.get('name');
const content = formData.get('content');
const post = {
name,
content
};
form.style.display = "none";
loadingElement.style.display= "";
fetch(API_URL, {
method: "POST",
body: JSON.stringify(post),
headers: {
"content-type": "application/json"
}
}).then(response => response.json())
.then(createdPost => {
console.log(createdPost);
});
});
server code
const express = require("express");
const cors = require('cors');
const monk = require("monk");
const app = express();
const db = monk("localhost/posts");
const posts = db.get("posts");
app.use(cors());
app.use(express.json());
app.get("/", (req, res) => {
res.json({
message: "Post"
});
});
function isValidPost(post){
return post.name && post.name.toString().trim() !== "" &&
post.content && post.content.toString().trim() !=="";
}
app.post("/posts", (req, res) => {
if (isValidPost(req.body)){
const post = {
name: req.body.name.toString(),
content: req.body.content.toString(),
created: new Date()
};
//console.log(post);
posts
.insert(post)
.then(createdPost => {
res.json(createdPost);
});
}else {
res.status(422);
res.json({
message: "Hey, Titel und Inhalt werden benötigt!"
});
}
});
app.listen(5000, () => {
console.log('Listening on http://localhost:5000');
});

Answer 1

You forgot to handle the case when post.insert(...) fails and rejects. In this case no response is sent from your server and the request will hang. Add the following:
posts
.insert(post)
.then(createdPost => {
res.json(createdPost);
})
.catch(err => {
console.log(err);
res.status(500).json({errorMessage: err.message});
});

Answer 2

handle the fetch method with catch. It probably goes to catch.
fetch().then().catch(err => ...)