This sample calculates the total for the second column value in a CSV file.
Each line in the CSV file has the following format:
date,amount

Here is the sample data that the script adds to the file:
10/21/14,200.0
10/21/15,210.2
10/21/16,250.3

Code Below:

require(['N/file', 'N/error', 'N/log'], function (file, error, log) {

// Create the CSV file
var csvFile = file.create({
name: 'data.csv',
contents: 'date,amount\n',
folder: 39,
fileType: 'CSV'
});

// Add the data
csvFile.appendLine({
value: '10/21/14,200.0'
});
csvFile.appendLine({
value: '10/21/15,210.2'
});
csvFile.appendLine({
value: '10/21/16,250.3'
});

// Save the file
var csvFileId = csvFile.save();

// Create a variable to store the calculated total