API to get data on google sheet

getGoogleSheetData.js

/*
  googleスプレッドシート内の情報を返すAPI
*/

function getDataOnSheet() {
  var SHEET_ID = PropertiesService.getScriptProperties().getProperty("SHEET_ID");
  var sht = SpreadsheetApp.openById(SHEET_ID).getSheets();
  var maxRow = sht[0].getLastRow();
  var data = sht[0].getRange(2, 1, maxRow - 1, 4).getValues();
  var ret = [];
  for (var r = maxRow - 2; r >= 0; r--) {
    ret.push(data[r].join("\t"));
  }
  return ret.join("\n");
}

function doGet(e) {
  var data = getDataOnSheet();
  return ContentService.createTextOutput(data);
}