Reset the content of a CSV file in the file cabinet - file

Question

I'm reading the content of a CSV file in the file cabinet with a user Event Suitelet living on sales orders and trying to reset the content of the file to an empty CSV after I'm done
I can successfully append lines and read the content but nothing about resetting the content in the NetSuite documentation.
I'm just looking for a way to reset the File to an empty CSV.
/**
*
#NApiVersion 2.x
#NModuleScope SameAccount
#NScriptType UserEventScript
#appliedtorecord salesorder
*/
define(['N/file'], function(file) {
function resetCSVFile(context) {
var fileObj = file.load({ id: '104819' });
var iterator = fileObj.lines.iterator();
var idArrays = [];
iterator.each(function(line) {
idArrays.push(line.value);
// the line below is my failed attempt at resetting the line
line.value = ''
return true;
});
log.audit({ title: 'idArrays', details: idArrays });
fileObj.save();
return true;
}
return {
afterSubmit: resetCSVFile
};
});

Answer 1

After you're done processing the file, you'll want to use file.create() to make a new file object with the same name, fileType, and folder property values. Set the contents property of that file object to something (perhaps the header row), and save it. This will overwrite the existing file with an empty file but keep the same internal id of the original file.
Here's an example that captures the header row of the CSV file and creates an empty file with that header row. When you create a file object, the contents property cannot be null or an empty string.
var fileObj = file.load({ id: '5447' });
var currentLine = 0;
var headerRow = '';
fileObj.lines.iterator().each(function(line) {
currentLine++;
if (currentLine === 1) {
headerRow = line.value + '\n';
}
log.debug({ title: 'header', details: line.value });
return true;
});
var newFile = file.create({
name: fileObj.name,
fileType: file.Type.CSV,
folder: fileObj.folder,
contents: headerRow
});
newFile.save();