mongo db transaction with multiple collection not working - mongodb

Question

the following function is supposed to do:
save the project into collection 'project_list'
push the uuid of the new project to a client in the collection 'client_list'
with transaction enabled, if anything goes wrong (such as the client id is given in the new project JSON object does not exist in the collection 'client_list'), then both step1 and step2 will be canceled.
noticed that the code is giving the client_id as 'invalid-uuid' to updateOne which will not add the project uuid to the client because the client_id does not exist in the collection but the new project is saved into collection 'project_list' with or without me doing commitTransaction.
I was reading this https://mongoosejs.com/docs/transactions.html which suggest me to abort the transaction by calling await session.abortTransaction(); but i dont know how to implement it.
thanks in advance.
transactionCreateProject: async function (newProjectJson) {
const mongoConnectConfig = {useNewUrlParser: true, useUnifiedTopology: true};
await mongoose.connect(CONSTANTS.ADMIN_MONGO_URL, mongoConnectConfig)
const db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error：'))
db.once("open", function (callback) {
console.log("Connection Succeeded")
});
let project = mongoose.model('project', mongooseProjectSchema)
let client = mongoose.model('client', mongooseClientSchema)
const session = await mongoose.startSession();
session.startTransaction();
try {
console.log(newProjectJson.clientUUID)
let newProjectMongooseObject = new project()
for (let i = 0; i < Object.keys(newProjectJson).length; i++){
// assigning the attributes of new project to mongoose object
newProjectMongooseObject[Object.keys(newProjectJson)[i]] = newProjectJson[Object.keys(newProjectJson)[i]]
}
newProjectMongooseObject['createdAt'] = dateObject.toISOString();
let saveRes = await newProjectMongooseObject.save()
let addProjectToClientRes = await clientMongooseModel.updateOne({ 'uuid': "invalid-uuid"}, {$push: {'projects': { projectID: newProjectJson.uuid}}})
}
catch (e) {
console.log(e)
return null
}
finally {
console.log("in finally, session ending")
session.endSession();
}
return null
},