Google App Script to imitate File - Import csv file into a sheet using a custom menu item

Question

How do I write a script that can let me select and upload a CSV file from local drive in a Google Spreadsheet when clicking on a custom menu ? (I want to replicate via script the File-->Import command but in a new menu being rendered onOpen).

There's a similar question here, but the answer uses a method that is now deprecated. Script import local CSV in Google Spreadsheet

Deprecated answer

function doGet(e) {
  var app = UiApp.createApplication().setTitle("Upload CSV to Sheet");
  var formContent = app.createVerticalPanel();
  formContent.add(app.createFileUpload().setName('thefile'));
  formContent.add(app.createSubmitButton('Start Upload'));
  var form = app.createFormPanel();
  form.add(formContent);
  app.add(form);
//  return app;
  SpreadsheetApp.getActiveSpreadsheet().show(app);// show app 
}

function doPost(e) {
  // data returned is a blob for FileUpload widget
  var fileBlob = e.parameter.thefile;

  // parse the data to fill values, a two dimensional array of rows
  // Assuming newlines separate rows and commas separate columns, then:
  var values = []
  var rows = fileBlob.contents.split('\n');
  for(var r=0, max_r=rows.length; r<max_r; ++r)
    values.push( rows[r].split(',') );  // rows must have the same number of columns

  // Using active sheet here, but you can pull up a sheet in several other ways as well
  SpreadsheetApp.getActiveSheet()
                .getRange( 1, 1, values.length, values[0].length )
                .setValues(values);
}

Answer 1

Instead of uploading it from local, it would be simpler to upload it from Google Drive.

Check-out the below code:

function importCSVFromGoogleDrive() {

  var file = DriveApp.getFilesByName("file.csv").next();
  var csvData = Utilities.parseCsv(file.getBlob().getDataAsString());
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('TEST').activate();
  sheet.getRange(1, 1, csvData.length, csvData[0].length).setValues(csvData);

}

This copies the data from "file.csv" in your Google Drive to the Sheet named "TEST" in your Spreadsheet.