Error Promise.all - node.js

Question

I'm trying to use Promise.all function but actually as I start nodeJS and I discover asynchronous technology I don't know where is my problem in my code...
Basically I would like to use Promise.all to make my own callback in a function then In my loop For I create several Promise and if I can save my data then I'll resolve my current Promise.
But apparently my promise.all is executed immediately and it don't wait for my others Promise..
See below ..
function persistMAP(jsonData,callback){
//Deck persistance
const promises =[];
for(var i=0; i<1; i++){
(function(i) {
var rowData = new DeckDatabase({
_id: new mongoose.Types.ObjectId(),
DeckNumber: Number(jsonData.Deck[i].DeckNumber),
x: Number(jsonData.Deck[i].x),
y: Number(jsonData.Deck[i].y),
});
rowData.save(function (err) {
if (err) return console.log(err);
for(var index=0; j=jsonData.Units.length,index<j; index++){
(function(index) {
promises.push(
new Promise(function(resolve,reject){
var unit = new MapDatabase({
UnitID:jsonData.Units[index].UnitID,
TypeID: Number(jsonData.Units[index].TypeID),
x: Number(jsonData.Units[index].x),
y: Number(jsonData.Units[index].y),
_id: mongoose.Types.ObjectId(((jsonData.Units[index].Code).toLowerCase()) + 'dd40c86762e0fb12000003'), // mongoose.Types.ObjectId(jsonData.Units[i].Code + 'dd40c86762e0fb12000003')
MainClass: jsonData.Units[index].MainClass,
Orientation: jsonData.Units[index].Orientation,
Postion: jsonData.Units[index].Postion,
Deck : String(rowData._id)
});
unit.save(function (err) {
if (err) {
reject();
throw err
}
else{
console.log('save');
resolve();
}
});
})
);
})(index);
}
});
})(i);
}
Promise.all(promises)
.then(()=>{
console.log('start find');
callback();
})
};
and here is where I call my function
else{
var jobj = JSON.parse(response.body);
console.log("persist begin");
persistMAP(jobj,function(){
console.log('retrieve Done');
MapDatabase.find()
.populate('Deck')
.exec(function(err, finalData){
console.log('send');
res.send(finalData);
})
});
}
So why It doesn't wait ? :(

Answer 1

You do an async operation in your for:
for(var i=0; i<1; i++){
....
rowData.save(function (err) {
So your promises array isn't filled with all the promise.
To loop async use async module :
var async = require("async");
var models = []; // my models array
// async loop, with 10 in same time, e is the element, i the index in models
async.eachOfLimit(models, 10, function(e, i, cb){
anAsyncFunction(function(err){
return cb(err);
});
}, function(err, result{
// all done
});