React async method setState variable not being set in time - reactjs

Question

I'm trying to run 3 methods after each other when a user clicks a button
Steps:
1: Push a file to IPFS, get the link back and assign it to a state variable
2: Add that link (from that var) to blockchain smart contract
3: Add an entry to the firebase database
The problem is that that IPFS link is null when I try to pass it to my smart contract, however after the method runs I can see the link print to console.
So I'm guessing it is not being set in time for the next method to see the variable.
IPFS Method:
pushToIPFS = async(e) => {
// e.preventDefault()
await ipfs.add(this.state.buffer, (err, ipfsHash) => {
console.log(err, ipfsHash)
//this.setState({IPFSlink : ipfsHash[0].hash})
console.log(ipfsHash[0].hash)
return ipfsHash[0].hash
})
}
Blockchain method:
addToBlockchain = async(e) => {
//create a new key for our student
var key = this.state.StudentNumber + this.state.account[0]
key = parseInt(hash(key), 10)
this.setState({idForBlockchain: key})
console.log(key)
//get todays date
let newDate = new Date()
newDate = newDate.getTime()
var _ipfsLink = this.state.IPFSlink
var _account = this.state.account[0]
console.log(_ipfsLink)
console.log(this.state.IPFSlink)
await storehash.methods.sendDocument(_ipfsLink, newDate,
}
Firebase method:
createStudent = async(e) => {
//get student details from state variables & current user uid
var _uid = this.state.uid
var _studentName = this.state.StudentName
var _studentNumber = this.state.StudentNumber
var _courseCode = this.state.CourseCode
var _courseName = this.state.CourseName
var _idForBlockchain = this.state.idForBlockchain
// database.ref.students.uid.studentNumber
const db = firebase.database()
db.ref().child("students").child(_uid).child(_studentNumber).set(
{ studentName: _studentName,
courseCode: _courseCode,
courseName: _courseName,
blockchainKey: _idForBlockchain
}
);
alert("Student added")
}
The method that triggers when the button is clicked:
AddMyStuff = async (e) => {
e.preventDefault()
await this.pushToIPFS()
await this.addToBlockchain()
await this.createStudent()
}
This is the error returned, so what I assume is the await and setState are causing issues and the variable I need is not being set.
Unhandled Rejection (Error): invalid string value (arg="_ipfsLocation", coderType="string", value=null, version=4.0.27)
Does anyone know how this can be solved?

Answer 1

you can convert your pushToIPFS to be a promise instead of a callback, and just resolve it when the callback is fired.
pushToIPFS = (e) => {
return new Promise((resolve, reject) => {
ipfs.add(this.state.buffer, (err, ipfsHash) => {
resolve(ipfsHash[0].hash);
})
});
}
And since its a promise you can use async/await.
AddMyStuff = async (e) => {
e.preventDefault()
const ipfsHash = await this.pushToIPFS();
//you have your ipfsHash defined, you can pass it to your other methods
}