How to create multi items/records or save item/record array at one time in client script file - google-app-maker

Question

I want to create multiple records at the same time using client script. This is what I'm doing:
var ceateDatasource = app.datasources.Reservation.modes.create;
var newItem = ceateDatasource.item;
newItem.User = user; //'eric'
newItem.Description = description; //'000'
newItem.Location_Lab_fk = lab.value.Id; //'T'
newItem.Area_fk = area.value.Id; //'L'
newItem.Equipment_fk = equipment.value.Id; //'S'
for(var i = 0 ; i < 3; i ++) {
newItem.Start_Date = startDate;
newItem.Start_Hours = '03';
newItem.Start_Minutes = '00';
newItem.End_Date = startDate;
newItem.End_Hours = '23';
newItem.End_Minutes = '30';
// Create the new item
ceateDatasource.createItem();
}
But the result I'm getting is this one:
The three records are created but the only the first one has data. The other two records have empty values on their fields. How can I achieve this?
Thanks.
Update(2019-3-27):
I was able to make it work by putting everything inside the for loop block. However, I have another question.
Is there any method like the below sample code?
var recordData = [Data1, Data2, Data3]
var ceateDatasource;
var newItem = new Array(recordData.length) ;
for(var i = 0 ; i < recordData.length; i ++) {
ceateDatasource = app.datasources.Reservation.modes.create;
newItem[i] = ceateDatasource.item;
newItem[i].User = recordData[i].user;
newItem[i].Description = recordData[i].Description;
newItem[i].Location_Lab_fk = recordData[i].Location_Lab_fk;
newItem[i].Area_fk = recordData[i].Area_fk;
newItem[i].Equipment_fk = recordData[i].Equipment_fk;
newItem[i].Start_Date = recordData[i].Start_Date;
newItem[i].Start_Hours = recordData[i].Start_Hours;
newItem[i].Start_Minutes = recordData[i].Start_Minutes;
newItem[i].End_Date = recordData[i].End_Date;
newItem[i].End_Hours = recordData[i].End_Hours;
newItem[i].End_Minutes = recordData[i].End_Minutes;
}
// Create the new item
ceateDatasource.createItem();
First, it prepares an array 'newItem' and only calls 'ceateDatasource.createItem()' one time to save all new records(or items).
I try to use this method, but it only saves the last record 'newItem[3]'.
I need to write a callback function in 'ceateDatasource.createItem()' but Google App Maker always show a warning "Don't make functions within a loop". So, are there any methods to call 'createItem()' one time to save several records? Or are there some functions like 'array.push' which can be used?
Thanks.

Answer 1

As per AppMaker's official documentation:
A create datasource is a datasource used to create items in a particular data source. Its item property is always populated by a draft item which can be bound to or set programmatically.
What you are trying to do is create three items off the same draft item. That why you see the result you get. If you want to create multiple items, you need to create a draft item for each one, hence all you need to do is put all your code inside the for loop.
for(var i = 0 ; i < 3; i ++) {
var ceateDatasource = app.datasources.Reservation.modes.create;
var newItem = ceateDatasource.item;
newItem.User = user; //'eric'
newItem.Description = description; //'000'
newItem.Location_Lab_fk = lab.value.Id; //'T'
newItem.Area_fk = area.value.Id; //'L'
newItem.Equipment_fk = equipment.value.Id; //'S'
newItem.Start_Date = startDate;
newItem.Start_Hours = '03';
newItem.Start_Minutes = '00';
newItem.End_Date = startDate;
newItem.End_Hours = '23';
newItem.End_Minutes = '30';
// Create the new item
ceateDatasource.createItem();
}
If you want to save several records at the same time using client script, then what you are looking for is the Manual Save Mode. So all you have to do is go to your model's datasource and click on the checkbox "Manual Save Mode".
Then use the same code as above. The only difference is that in order to persist the changes to the server, you need to explicitly save changes. So all you have to do is add the following after the for loop block:
app.datasources.Reservation.saveChanges(function(){
//TODO: Callback handler
});