Export json google sheet

export-json.gs

function doGet() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Data");
  var range = sheet.getDataRange();
  var values = range.getValues();
  var headers = values[0];
  var data = values.slice(1);
  var json = {};

  for (var col = 0; col < headers.length; col++) {
    var header = headers[col];
    json[header] = [];

    for (var row = 0; row < data.length; row++) {
      if (data[row][col] != "") {
        json[header].push(data[row][col]);
      }
    }
  }

  var output = ContentService.createTextOutput(JSON.stringify(json));
  output.setMimeType(ContentService.MimeType.JSON);
  return output;
}