Downloading a SQL database as a CSV instead of select rows - google-apps-script

Question

I used a function to download some selections from a Lists object as a CSV. I'd like to do the same for the entire datasource connected to the Lists object, but am unsure of how to scale this to work with, as an example, 100,000 rows. On the button to download the List data as a CSV I have:
var rows = widget.root.descendants.MainTableBody.children._values;
var csvdata = [];
csvdata.push([["Email"],["Last Login"],["Sku ID"],["Sku Name"],["Docs Added Recently"]]);
for (var i in rows) {
var t = [];
t.push(rows[i].children.EmailField.text);
t.push(rows[i].children.LastLoginField.text);
t.push(rows[i].children.SkuIdField.text);
t.push(rows[i].children.SkuNameField.text);
t.push(rows[i].children.DocsAddedField.text);
csvdata.push(t);
}
console.log(csvdata);
exportToCsv("LMexport",csvdata);
The export function is taken from this answer.I basically need the rows var to cover the entire table, but that's a lot of data.
The schema of the datasource in question:
and the calculation used:
Here's what the table looks like in the UI for reference:

Answer 1

Records retrieved from query are array of objects
You can use .reduce to convert them to csv
Snippet:
function exportCsv(){
var query = app.models.Employees.newQuery();
//query.filters.... use query used to populate the datasource
var records = query.run(); //[{},{},{}...]
var csv = records.reduce(function(str, rec){
var email = rec.Email;
var login = rec.LastLogin;
var skuId = rec.SkuId;
return str + '"' + [email,login,skuId].join('","') + '"\n'; // result: "email","login","skuId"\n
},'');
return csv;
}