Trouble Uncompressing Zip and then parsing CSV with Google Apps Script - google-apps-script

Question

Trying to create a Google Apps Script that reads emails from a specific email address and copy the contents of a CSV file into a Google sheet.
Problem is sometimes the files come in as zip attachments. I'm trying to work logic into the script to uncompress the zip if it's a zip attachment and then post the data to the Google sheet.
Currently getting the following error message: Cannot find function getDataAsString in object Blob.
Any ideas / recommendations for getting this to work with potential zip files would be great.
You can find my full code below:
function myFunction() {
var threads = GmailApp.search("from:testemail#example.com");
var message = threads[0].getMessages()[0];
var attachment = message.getAttachments()[0];
Logger.log(attachment.getContentType());
// Is the attachment a CSV file
if (attachment.getContentType() === "text/csv") {
var sheet = SpreadsheetApp.getActiveSheet();
var csvData = Utilities.parseCsv(attachment.getDataAsString(), ",");
Logger.log("Found a CSV file");
// Remember to clear the content of the sheet before importing new data
sheet.clearContents().clearFormats();
sheet.getRange(1, 1, csvData.length, csvData[0].length).setValues(csvData);
}
if (attachment.getContentType() === "application/zip") {
var sheet = SpreadsheetApp.getActiveSheet();
var files = Utilities.unzip(attachment);
Logger.log(files);
var newDriveFile = DriveApp.createFile(files[0]);
var csvData = Utilities.parseCsv(files.getDataAsString(), ",");
Logger.log("Found a ZIP file");
// Remember to clear the content of the sheet before importing new data
sheet.clearContents().clearFormats();
sheet.getRange(1, 1, csvData.length, csvData[0].length).setValues(csvData);
}
}

Answer 1

Utilities.unzip will return array of blobs. So you need to refer the particular blob inside the array of blobs. Just modify the below code snippet.
var files = Utilities.unzip(attachment)[0];
Also, it is safe to mention the charset so that special characters are displayed properly.
var csvData = Utilities.parseCsv(attachment.getDataAsString('ISO-8859-1'), ",");
Entire Function:
function exportData() {
var threads = GmailApp.search("from:testemail#example.com");
var message = threads[0].getMessages()[0];
var attachment = message.getAttachments()[0];
Logger.log(attachment.getContentType());
// Is the attachment a CSV file
if (attachment.getContentType() === "text/csv") {
var sheet = SpreadsheetApp.getActiveSheet();
var csvData = Utilities.parseCsv(attachment.getDataAsString('ISO-8859-1'), ",");
Logger.log("Found a CSV file");
// Remember to clear the content of the sheet before importing new data
sheet.clearContents().clearFormats();
sheet.getRange(1, 1, csvData.length, csvData[0].length).setValues(csvData);
}
if (attachment.getContentType() === "application/zip") {
var sheet = SpreadsheetApp.getActiveSheet();
var files = Utilities.unzip(attachment)[0];
var csvData = Utilities.parseCsv(files.getDataAsString('ISO-8859-1'), ",");
Logger.log("Found a ZIP file");
// Remember to clear the content of the sheet before importing new data
sheet.clearContents().clearFormats();
sheet.getRange(1, 1, csvData.length, csvData[0].length).setValues(csvData);
}
}