I have a program where, upon clicking a button, the "likes" attribute of a randomly fetched MongoDB document is supposed to update. However, it does not. I am able to call the fetched document through the button, not not actually update it:
MongoClient.connect(DBconnection, { useUnifiedTopology: true })
.then(client => {
const db = client.db(database);
const collection = db.collection(table);
//R has been previously defined as a random number
let doc = function(data) {
return db.collection(table).find().limit(-1).skip(R - 1).next()
.then(results => { return results })
}
//This is supposed to update the value of the randomly fetched document
app.post("/", (req, res) => {
let w = doc()
w.then(function(results) {
console.log(results) //This correctly returns the random document
})
//This line is meant to update document "w", but it does not.
db.collection(table).updateOne({ w }, { $set: { likes: "clicked" + R } })
.then(result => {
res.redirect("/")
})
.catch(error => console.error(error))
});
});
The button in the ejs file is as simple as:
<form action="/" method="POST">
<button id="updoot" type="submit">upvote</button>
</form>
Check the status of the promise by console logging (result). If it returns a pending promise, try async-await which will resolve the promise, and then executes res.redirect.
app.post("/", async (req, res) => {
let w = await doc()
const updatedData = await db.collection(table).updateOne({ w }, { $set: { likes: "clicked" + R } })
res.redirect("/")
});
I think it should work.
Alright, thanks to the contribution of jkalandarov, I was able to solve it just by adding one extra step: requesting the ObjectId of w and using that as a filter instead of the returned promise of w:
app.post("/", async (req, res) => {
let w = await doc()
var oid = w._id
let updatedData = await db.collection(table).updateOne({"_id":ObjectId(oid)}, { $set: { likes: "clicked" + R } })
res.redirect("/")
});