async and await function Node.js - node.js

Question

I have followed this tutorial to upload files into IPFS using Node.js, but I had a problem which doesn't appear in the tutorial!
It is related to with Async and await function, I can't make this statement
const fileHash = fileAdded[0].hash;
I tried with await
const fileAdded = await ipfs.add({path: Name, content: file});
but unfortunately, I got an error which is (hash undefined).
I tried with a callback function, but I'm not sure about my way because (fileAdded) variable didn't give me any answer and also it was undefined,
this is a full code:
const ipfsClient = require('ipfs-http-client');
const express = require('express');
const bodyParser = require('body-parser');
const fileUpload = require('express-fileupload');
const fs= require('fs');
const ipfs = new ipfsClient({host: 'localhost', port: '5001', protocol: 'http'});
const app= express();
var hash = require('hash');
app.set('view engine', 'ejs');
app.use(bodyParser.urlencoded({extended:true}));
app.use(fileUpload());
app.get('/',(req,res)=>{
res.render('home');
});
app.post('/upload',(req,res)=>{
const f= req.files.file;
const Name = req.files.file.name;
const filePath ="files/"+ Name;
f.mv(filePath,async(err)=>{
if(err){
console.log("error failed to download a file");
return res.status(500).send(err);
}
const fileh = await addFile(Name,filePath);
fs.unlink(filePath, (err)=>{
if(err) console.log("error");
});
res.render('upload',{Name,fileh});
});
});
const addFile= async(Name,filePath)=> {
const file=fs.readFileSync(filePath);
const fileAdded = await ipfs.add({path: Name, content: file});
const fileHash = fileAdded[0].hash;
return fileHash;
};
app.listen(3000,()=>{
console.log("server is listen");
});
this is the error appears:
i write a callback function like that :
const addFile= async(Name,filePath)=> {
const file=fs.readFileSync(filePath);
const fileAdded = await ipfs.add({path: Name, content: file},(err,res)=>{
if(err)
console.log(err);
const fileHash = fileAdded[0].hash;
return fileHash;});};
but the value of fileAdded and fileHash was undefined.
after i use this code from #Always Learning :
const addFile= async(Name,filePath)=> {
const file=fs.readFileSync(filePath);
const hashes = [];
const filesAdded = ipfs.add({path: Name, content: file});
for await (const result of filesAdded) {
hashes.push(result.hash);
console.log(result.hash);
console.log(result);
}
return hashes; // if you know it's just one for example
};
It gave me an information of a file, but hash does not work as it gave me undefined, I want extract just a hash like this "QmRndAYkvH3D2qhmYfaAZvWT6MDi4NiJPbzJor3EL87rrb"

Answer 1

Since ipfs.add() returns an async-iterable object, you need to use for async to go through it like this:
const addFile= async(Name,filePath)=> {
const file=fs.readFileSync(filePath);
const hashes = [];
const filesAdded = ipfs.add({path: Name, content: file});
for await (const result of filesAdded) {
if (result.hash) {
hashes.push(result.hash);
} else if (result.cid) {
hashes.push(result.cid.multihash); // guessing here - might be another part of the cid object
} else {
console.log("No hash found in",result);
}
}
return hashes[0]; // if you know it's just one for example
};

Answer 2

You have to change this:
const fileHash = fileAdded[0].hash;
into this:
const fileHash = fileAdded.hash;
(so remove [0]).
This worked for me: it has to do with the libraries.