examples of simple triggers with google apps script

Code.gs

/**
 * These simple triggers are available in Sheets, Docs, and Forms
 * Most of this information can be found:
 * https://developers.google.com/apps-script/guides/triggers/events
 */
function onOpen(e) {
  //  {
  //    authMode: 'LIMITED',
  //    source: 'Spreadsheet' || 'Document' || 'Form',
  //    user: 'User'
  //  }
  var user = e.user;
  var authMode = e.authMode;
  var source = e.source;
  //  SpreadsheetApp.getActiveSpreadsheet()
  //  DocumentApp.getActiveDocument()
  //  FormApp.getActiveForm() **This is triggered when the form is opened for editing
}

function onInstall(e) {
  // This event is used when developing add-ons
  // { authMode: 'LIMITED' or 'FULL' }
  
  // You can run other simple triggers here
  onOpen();
}

/**
 * onEdit is a simple trigger that is available in Sheets
 */
function onEdit(e) {
  // event object parameters:
  //  authMode
  //  source
  //  user
  //  range
  //  value
  //  oldValue
}

/**
 * doGet and doPost are simple triggers that are used by web apps built with apps script
 * They pass an event object that is similar
 */
function doGet(e) {
  e.queryString;
  // The value of the query string portion of the URL, or null if no query string is specified
  // ex. name=alice&n=1&n=2
  
  e.parameter;
  // An object of key/value pairs that correspond to the request parameters. 
  // Only the first value is returned for parameters that have multiple values.
  // ex. {"name": "alice", "n": "1"}
  
  e.parameters;
  // An object similar to e.parameter, but with an array of values for each key
  // ex. {"name": ["alice"], "n": ["1", "2"]}
  
  // You can read more about the rest in the documentation
  // https://developers.google.com/apps-script/guides/web
  e.contextPath;
  e.contentLength;
  e.postData.length;
  e.postData.type; // the MIME type of the POST body
  
}

doGet-and-doPost.gs

function doGet(e) {
//  var user = e.parameter.user || 'Anonymous';
  var user = e.parameter.user || Session.getActiveUser().getEmail();
  
  var age = e.parameter.age || 'ageless';
  
  return HtmlService.createHtmlOutput(user + ' is aged ' + age);
}

onEdit.gs

function onEdit(e) {
  var row = e.range.getRow();
  var column = e.range.getColumn();
  
  // You don't always have to use the event object to target cells
  var adjacentCell = SpreadsheetApp.getActiveSheet().getRange(row, column + 1);
  
  var newValue = (typeof e.value !== 'object') ? e.value : 0;
  var oldValue = e.oldValue;
  
  if(newValue && newValue > oldValue) {
    adjacentCell.setValue('New value increased');
  } else if(newValue && newValue < oldValue) {
    adjacentCell.setValue('New value decreased');
  } else if(newValue && newValue == oldValue) {
    adjacentCell.setValue('Values the same');
  } else {
    adjacentCell.clear();
  }
}

onOpen.gs

function onOpen(e) {
  var today = new Date();
  
  // A really annoying thing is there is no autocomplete on event objects!
  var body = e.source.getBody();
  
  body.appendParagraph(today.toDateString() + ' - ' + today.toTimeString())
    .appendHorizontalRule();
}