storing file with Large Object Postgres with Nodejs - node.js

Question

I have a simple HTML form with a file input. I need to save the file with Postgres Large Object but I'm having issues with the fileStream.pipe. It should be in a Promise itself like so:
return new Promise((resolve, reject) => {
stream.on('finish', resolve(oid));
stream.on('error', reject);
});
But it wouldn't work since it would result into a Promise in a Promise. The complete functions are:
function storeLargeObject(path) {
return new Promise((resolve, reject) => {
pgp.db.tx(tx => {
const man = new LargeObjectManager({pgPromise: tx});
return man.createAndWritableStreamAsync(bufferSize);
}).then(([oid, stream]) => {
const fileStream = createReadStream(path);
fileStream.pipe(stream);
stream.on('finish', resolve(oid));
stream.on('error', reject);
}).catch(err => {
console.log(err);
return err;
});
});
}
const addBinary = (req, res) => {
pgp.db.oneOrNone({
text: insertQuery,
values: values
}).then(f => {
let explFile = req.files.bin;
let uploadPath = __dirname + '/' + f.id;
if (!req.files || Object.keys(req.files).length === 0) {
res.status(400).send('No File was uploaded.');
return;
}
explFile.mv(uploadPath, async function (err) {
if (err)
return res.status(500).send(err);
let newOid = await storeLargeObject(uploadPath);
fs.unlink(uploadPath, err => console.log(err));
coupleIds(exp.id, newOid);
return res.status(200).send({
status: "success",
message: "File successfully uploaded!"
})
});
}).catch(err => {
return res.status(401).send({
status: 'error',
errorCode: 102,
message: 'Error! ' + err
});
});
}