menuEmail, Calendar, and Dates

Lesson 14: Email, Calendar, and Dates

Learning Objectives

  1. Send email from Apps Script with MailApp, and explain why it's safer than GmailApp for sending.
  2. Check a script's permissions on the permission screen, even when an assistant describes them.
  3. Create and work with dates: build one, read its parts, add days, and format it as text.
  4. Write a "dry run" that logs what code would do before it does anything that can't be undone.
  5. Create Google Calendar events from a script.

14.1 Sending Email

Until now, your scripts have only changed the club's spreadsheet, and a mistake could be undone with Edit, then Undo. This lesson's scripts reach outside the spreadsheet: they send email and create calendar events. An email can't be unsent, so the Read step matters more than ever.

The club's first email: a welcome message for each new sign-up. It builds on the form-submit trigger from Lesson 13. Menus and Triggers. Here's the request, in a new chat with your learner profile from that lesson and the garden context:

(Paste the garden context first.) When someone submits the sign-up form, send them a short welcome email from the club that uses their first name and mentions the interests they chose.send

Before I write this, there's one new tool you'll need that isn't in your list: GmailApp.sendEmail(recipient, subject, body). It's a method (like the ones you already know) that sends an email. You give it three strings — who to send it to, the subject line, and the message body — and Gmail sends the message. I'll use it here since there's no other way to send email.

Here's the code:

function sendWelcomeEmail(e) {
  // e is the event object Google Sheets creates when the form is submitted
  // e.namedValues holds the answers, grouped by the column header they came from

  const namedValues = e.namedValues

  // Each answer is stored as an array with one item, so we use [0] to get it
  const firstName = namedValues["First Name"][0]
  const email = namedValues["Email"][0]
  const interests = namedValues["Interests"][0]

  // Build the subject line and message using template literals
  const subject = `Welcome to the Club, ${firstName}!`
  const body = `Hi ${firstName},\n\nThanks for signing up! We're glad you're interested in: ${interests}.\n\nWe'll be in touch soon.\n\n- The Garden Club`

  // Send the email
  GmailApp.sendEmail(email, subject, body)
}

How to set up the trigger

This function needs to run automatically whenever the form is submitted, so it needs an installable trigger (not a simple one, since simple triggers can't send email):

  1. In the Apps Script editor, click the clock icon on the left (Triggers).
  2. Click Add Trigger.
  3. Set:
    • Function to run: sendWelcomeEmail
    • Event source: From spreadsheet
    • Event type: On form submit
  4. Save.

How to test it without submitting the form

You can call the function yourself with a made-up event object, so you don't have to wait for a real form submission:

function testSendWelcomeEmail() {
  // This fake event object copies the shape of a real one
  const fakeEvent = {
    namedValues: {
      "First Name": ["Ava"],
      "Email": ["your-own-email@example.com"],
      "Interests": ["watering, composting"]
    }
  }

  sendWelcomeEmail(fakeEvent)
}

Run testSendWelcomeEmail from the Apps Script editor (choose it from the function dropdown, then click Run). Use your own email address in the fake data so you can check that the message arrives and looks right.

Would you like me to also add a check for interests being blank, in case someone submits the form without checking any?

Reply from Claude, captured September 26, 2026

Read. The function reads the answers from e.namedValues, as in the last lesson, builds a subject and a body with template literals, and sends the message with GmailApp.sendEmail, which takes three strings: the address, the subject and the body. In the body, \n means a new line, so \n\n leaves a blank line between paragraphs.

The new rule in your profile worked. Without being asked, the assistant explained how to set up the trigger and wrote a test function with a made-up event, and it told you to put your own email address in the test, so the only message sent goes to you. That's exactly how to test code that sends email.

\n — In a string, a backslash followed by n stands for a line break. "Hi Ava,\n\nThanks" is two lines with a blank line between them.

14.1.1 Checking the permissions

Sending email is powerful access to give a script, so it's worth asking about:

What permissions will GmailApp ask for when I run this? Is there a way to send email that needs less access to my account?send

Good question — this matters for both privacy and trust when you share your script with others.

What GmailApp asks for

Since we're only calling sendEmail, Google will ask for permission to "Send email as you" — a fairly narrow permission. It does not ask for permission to read your inbox, see your contacts, or delete anything.

However, GmailApp is a big service that can do many other things — read messages, manage labels, search your inbox, etc. Because of that, if your script ever uses any of those other GmailApp features later, Google may expand the permission request to cover full Gmail access.

A more limited option: MailApp

There's a separate, smaller service called MailApp that can only send email — nothing else. It has the exact same method signature:

MailApp.sendEmail(recipient, subject, body)

Because MailApp can't do anything except send mail, Google will only ever ask for the narrow "send email" permission, no matter what else your script does. This makes it a safer choice when sending email is the only Gmail-related thing your script needs to do.

Updated function using MailApp

function sendWelcomeEmail(e) {
  const namedValues = e.namedValues

  const firstName = namedValues["First Name"][0]
  const email = namedValues["Email"][0]
  const interests = namedValues["Interests"][0]

  const subject = `Welcome to the Club, ${firstName}!`
  const body = `Hi ${firstName},\n\nThanks for signing up! We're glad you're interested in: ${interests}.\n\nWe'll be in touch soon.\n\n- The Garden Club`

  // MailApp only sends email — it can't read or manage your Gmail account
  MailApp.sendEmail(email, subject, body)
}

Everything else — the trigger setup and the test function — stays exactly the same, since MailApp.sendEmail takes the same three arguments as GmailApp.sendEmail.

One small trade-off: MailApp has a daily sending quota, similar to GmailApp, but it doesn't let you do fancier things later (like reading replies or searching your inbox) if your club ever wants that. For a simple welcome email like this, though, MailApp is a good, safer fit.

Want me to switch the earlier code over to MailApp for good?

Reply from Claude, captured September 26, 2026

The advice to use MailApp is good. It can only send email, so it's the right tool when sending is all you need, and its sendEmail takes the same arguments.

But the first part of the answer is wrong. At the time of writing, a script that uses GmailApp at all asks for permission to "Read, compose, send, and permanently delete all your email from Gmail," not just to send. Apps Script decides what to ask for from which services your code uses, not from which of their methods it calls. MailApp asks only to "Send email as you."

You don't have to take the book's word for this either. The permission screen is the final word: run the test function and read what it asks for. That's the habit from Lesson 4. Getting Started with Google Apps Script in Google Sheets, and this is a case where it catches an assistant's mistake. If you see a request for full Gmail access for a script that only sends mail, switch to MailApp.

Here's the welcome email in the book's style, with MailApp and a test function first:

function testSendWelcomeEmail() {
  // use your own address, so the only email sent goes to you
  const fakeEvent = {
    namedValues: {
      "First Name": ["Test"],
      "Email": ["your.own.address@example.com"],
      "Interests": ["Hydroponics, Pollinator Gardens"]
    }
  }
  sendWelcomeEmail(fakeEvent)
}

function sendWelcomeEmail(e) {
  const answers = e.namedValues
  const firstName = answers["First Name"][0]
  const email = answers["Email"][0]
  const interests = answers["Interests"][0]

  const subject = `Welcome to the College Community Garden, ${firstName}!`
  const body = `Hi ${firstName},\n\nThanks for signing up! We're glad you're interested in ${interests}.\n\nSee you in the garden,\nThe College Community Garden`

  MailApp.sendEmail(email, subject, body)
}

Change the address in the test to your own before you run it. Once it arrives and looks right, set up an on-form-submit trigger for sendWelcomeEmail. A project can have several form-submit triggers, one for adding the member and one for the welcome email.

Email can't be unsent. Test with your own address, send to one person before many, and read every line that decides who receives a message. Google also limits how many emails a script can send each day. For a free Google account, the limit is about 100 recipients a day at the time of writing, which is plenty for a club but easy to hit with a loop that goes wrong.

14.2 Dates in JavaScript

Reminders, calendars and schedules all need dates. JavaScript represents a moment in time with a Date object. new Date() with nothing in the parentheses creates one for right now:

const now = new Date()
console.log(now)
console.log(now.getFullYear())
console.log(now.getMonth())
console.log(now.getDate())
console.log(now.getDay())

The methods that read a date's parts have some surprises:

new Date is written with the word new, which creates a new object of a built-in type. You'll see new with a few other built-in types later.

Date object — A value representing one moment in time, created with new Date(). Its methods read and change its parts, such as getFullYear(), getMonth() (counting from 0) and getDate().

To create a particular date, give new Date the year, month, day and, optionally, hour and minute. The month counts from 0 here too:

// May is month 4, because months count from 0
const workday = new Date(2027, 4, 1, 9, 0)
console.log(workday)
console.log(workday.getDay())

getDay() gives 6, so May 1, 2027 is a Saturday.

To move a date forward or back, change its day with setDate. JavaScript handles the ends of months for you:

const day = new Date(2027, 4, 29)
day.setDate(day.getDate() + 7)
console.log(day.getMonth() + 1, day.getDate())

May 29 plus 7 days is June 5, and JavaScript rolled over into June by itself.

14.2.1 Dates as text

The club's spreadsheet stores dates as text, like "2027-04-18", as you saw in Lesson 10. College Community Garden: Case setup: College Community Garden: Case Setup. Turning a date into text in that form means building it from its parts, with a leading zero for months and days below 10. Apps Script also has a tool that does it in one step, Utilities.formatDate:

const today = new Date()
const timeZone = Session.getScriptTimeZone()
const dateText = Utilities.formatDate(today, timeZone, "yyyy-MM-dd")

The pattern "yyyy-MM-dd" means four-digit year, two-digit month, two-digit day. (Capital MM is month; lowercase mm is minutes.) The time zone matters because "today" depends on where you are: at 11 p.m. in California, it's already tomorrow in London. Session.getScriptTimeZone() uses the time zone in your project's settings.

Going the other way, from text to a Date, has a trap:

const date = new Date("2027-04-18")
console.log(date.getDate())

If you're in the Americas, this probably displays 17, not 18. JavaScript reads a date written this way as midnight in London time (UTC, to be exact), and midnight in London is the previous evening in the Americas. Unless you need a Date object, the simplest way to compare text dates is to turn the date you have into the same text form, and compare the strings. That's what the next example does.

14.3 Shift Reminders

Each Friday, the club wants to remind everyone with a shift the next day. Here's the request, with the garden context. It tells the assistant which Date methods you know, and asks for a dry run: log each email instead of sending it.

(Paste the garden context first.) Every Friday, I want to email each member who has a shift the next day (Saturday), telling them the task and how many hours. I know the Date object: new Date(), getFullYear, getMonth, getDate, getDay, and adding days with setDate. For now, don't send anything: log each email instead, so I can check them first.send

Here's a plan: I'll break this into three functions.

  1. getTomorrowDateText() — figures out tomorrow's date and turns it into the same text format used in your sheet ("2027-04-10").
  2. findMemberFirstName(email, membersData) — looks up a member's first name by their email, so the email can start with "Hi [Name]".
  3. logShiftEmailsForDate(dateText) — does the real work: finds every shift on a given date and logs what the email would say.
  4. logSaturdayShiftEmails() — the function you'll actually put on a trigger. It just calls logShiftEmailsForDate with tomorrow's date.

Splitting it this way means I can test the logic by calling logShiftEmailsForDate with a date I type in myself, instead of waiting for tomorrow.

// Works out tomorrow's date as text like "2027-04-10"
function getTomorrowDateText() {
  const today = new Date()
  const tomorrow = new Date()
  tomorrow.setDate(today.getDate() + 1)

  const year = tomorrow.getFullYear()
  const monthNumber = tomorrow.getMonth() + 1  // getMonth counts from 0, so add 1
  const dayNumber = tomorrow.getDate()

  // Build a two-digit month, adding a leading zero if needed
  let monthText = String(monthNumber)
  if (monthNumber < 10) {
    monthText = `0${monthNumber}`
  }

  // Build a two-digit day, adding a leading zero if needed
  let dayText = String(dayNumber)
  if (dayNumber < 10) {
    dayText = `0${dayNumber}`
  }

  const dateText = `${year}-${monthText}-${dayText}`
  return dateText
}

// Looks through the Members data for a matching email and returns the first name
// Returns "" if no match is found
function findMemberFirstName(email, membersData) {
  let firstName = ""

  for (let i = 1; i < membersData.length; i++) {
    const memberEmail = membersData[i][2]  // column C

    if (memberEmail === email) {
      firstName = membersData[i][0]  // column A
    }
  }

  return firstName
}

// Finds every shift on the given date and logs the email that would be sent
function logShiftEmailsForDate(dateText) {
  const shiftsSheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Shifts")
  const shiftsData = shiftsSheet.getDataRange().getValues()

  const membersSheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Members")
  const membersData = membersSheet.getDataRange().getValues()

  for (let i = 1; i < shiftsData.length; i++) {
    const shiftDate = shiftsData[i][0]

    if (shiftDate === dateText) {
      const task = shiftsData[i][1]
      const email = shiftsData[i][2]
      const hours = shiftsData[i][3]

      const firstName = findMemberFirstName(email, membersData)

      const subject = `Reminder: your shift tomorrow`
      const body = `Hi ${firstName}, this is a reminder that you have a ${task} shift tomorrow (${dateText}) for ${hours} hours.`

      Logger.log(`To: ${email}`)
      Logger.log(`Subject: ${subject}`)
      Logger.log(`Body: ${body}`)
    }
  }
}

// This is the function to put on a weekly Friday trigger
function logSaturdayShiftEmails() {
  const tomorrowText = getTomorrowDateText()
  logShiftEmailsForDate(tomorrowText)
}

How to test it right now (without waiting for Friday)

Add a temporary test function like this, using a date you know is in your Shifts sheet:

function testLogShiftEmailsForDate() {
  logShiftEmailsForDate("2027-04-10")
}

Run testLogShiftEmailsForDate from the Apps Script editor's function dropdown, then check the Execution log (View > Logs, or the log icon) to see what would have been emailed.

Setting up the real trigger

  1. In the Apps Script editor, click the clock icon on the left (Triggers).
  2. Click Add Trigger.
  3. Set "Choose which function to run" to logSaturdayShiftEmails.
  4. Set "Select event source" to Time-driven.
  5. Set "Select type of time based trigger" to Week timer.
  6. Set the day to Every Friday and pick a time range (like 6am–7am).
  7. Click Save.

Once you've checked the logged emails and they look right, let me know and we can change Logger.log to MailApp.sendEmail to actually send them.

Reply from Claude, captured September 26, 2026

Read. Four functions (the reply says three, then lists four):

This design is worth noticing. The function that does the work takes the date as a parameter, rather than working out "tomorrow" itself. That means you can test it with any date, today, without waiting for a Friday. The test function the assistant suggested does exactly that, with a date from the sheet.

The approach to dates is also sound: instead of turning the sheet's text into Date objects, it turns tomorrow's date into text, and compares strings. That avoids the time-zone trap above entirely. (The reply mentions View, then Logs, once more. The Execution log opens on its own.)

Here's the test on this page, with the Shifts and Members sheets. The test function comes first, so it's the one selected. On April 10, 2027, three members had shifts: Dev, Farah and Hana.

{"sheetName": "Shifts", "rows": 87, "columns": 5, "data": [{"range": "A1:D84", "values": [["Date", "Task", "Member Email", "Hours"], ["2027-03-20", "composting", "ava.lopez@example.com", 1], ["2027-03-20", "planting", "cam.nguyen@example.com", 1], ["2027-03-20", "watering", "dev.patel@example.com", 1.5], ["2027-03-20", "composting", "isaac.cohen@example.com", 1], ["2027-03-20", "harvesting", "keisha.brown@example.com", 1.5], ["2027-03-20", "watering", "maya.thompson@example.com", 1], ["2027-04-03", "watering", "elena.rossi@example.com", 1], ["2027-04-03", "planting", "maya.thompson@example.com", 1], ["2027-04-10", "planting", "dev.patel@example.com", 1], ["2027-04-10", "watering", "farah.haddad@example.com", 1.5], ["2027-04-10", "watering", "hana.kim@example.com", 1.5], ["2027-04-17", "watering", "maya.thompson@example.com", 2], ["2027-04-24", "planting", "ava.lopez@example.com", 2], ["2027-04-24", "watering", "keisha.brown@example.com", 2], ["2027-05-01", "watering", "farah.haddad@example.com", 1], ["2027-05-01", "harvesting", "hana.kim@example.com", 2], ["2027-05-01", "weeding", "keisha.brown@example.com", 1], ["2027-05-01", "harvesting", "maya.thompson@example.com", 1.5], ["2027-05-01", "composting", "maya.thompson@example.com", 2], ["2027-05-08", "composting", "dev.patel@example.com", 1], ["2027-05-15", "watering", "dev.patel@example.com", 2], ["2027-05-15", "planting", "elena.rossi@example.com", 1], ["2027-05-15", "watering", "isaac.cohen@example.com", 1.5], ["2027-05-15", "weeding", "maya.thompson@example.com", 2], ["2027-05-22", "weeding", "dev.patel@example.com", 1], ["2027-05-22", "composting", "farah.haddad@example.com", 1], ["2027-05-22", "weeding", "farah.haddad@example.com", 1], ["2027-05-22", "weeding", "hana.kim@example.com", 1.5], ["2027-05-22", "watering", "hana.kim@example.com", 2], ["2027-05-22", "weeding", "keisha.brown@example.com", 1], ["2027-05-29", "harvesting", "dev.patel@example.com", 1.5], ["2027-05-29", "planting", "hana.kim@example.com", 1.5], ["2027-05-29", "weeding", "keisha.brown@example.com", 2], ["2027-06-05", "planting", "farah.haddad@example.com", 1], ["2027-06-05", "weeding", "hana.kim@example.com", 1.5], ["2027-06-05", "weeding", "hana.kim@example.com", 2], ["2027-06-12", "planting", "dev.patel@example.com", 1.5], ["2027-06-12", "harvesting", "maya.thompson@example.com", 1.5], ["2027-06-19", "planting", "cam.nguyen@example.com", 1.5], ["2027-06-19", "composting", "cam.nguyen@example.com", 1.5], ["2027-06-19", "watering", "hana.kim@example.com", 1], ["2027-06-19", "weeding", "keisha.brown@example.com", 2], ["2027-06-19", "watering", "maya.thompson@example.com", 1.5], ["2027-07-03", "weeding", "ava.lopez@example.com", 1], ["2027-07-03", "watering", "ava.lopez@example.com", 2], ["2027-07-03", "harvesting", "farah.haddad@example.com", 2], ["2027-07-10", "harvesting", "cam.nguyen@example.com", 1], ["2027-07-10", "weeding", "isaac.cohen@example.com", 1.5], ["2027-07-10", "watering", "maya.thompson@example.com", 2], ["2027-07-17", "harvesting", "farah.haddad@example.com", 1.5], ["2027-07-17", "watering", "hana.kim@example.com", 1.5], ["2027-07-24", "watering", "ava.lopez@example.com", 2], ["2027-07-24", "harvesting", "gabe.martinez@example.com", 2], ["2027-07-24", "weeding", "hana.kim@example.com", 1.5], ["2027-07-24", "composting", "maya.thompson@example.com", 2], ["2027-07-31", "watering", "ben.okafor@example.com", 2], ["2027-07-31", "planting", "cam.nguyen@example.com", 1.5], ["2027-07-31", "watering", "elena.rossi@example.com", 1.5], ["2027-08-07", "weeding", "ava.lopez@example.com", 2], ["2027-08-14", "watering", "ben.okafor@example.com", 2], ["2027-08-14", "planting", "cam.nguyen@example.com", 1.5], ["2027-08-14", "watering", "elena.rossi@example.com", 1.5], ["2027-08-21", "composting", "dev.patel@example.com", 1.5], ["2027-08-21", "composting", "hana.kim@example.com", 1.5], ["2027-08-28", "weeding", "cam.nguyen@example.com", 1.5], ["2027-08-28", "composting", "dev.patel@example.com", 1], ["2027-08-28", "composting", "hana.kim@example.com", 1], ["2027-09-04", "harvesting", "dev.patel@example.com", 1.5], ["2027-09-04", "weeding", "farah.haddad@example.com", 1], ["2027-09-04", "watering", "isaac.cohen@example.com", 1.5], ["2027-09-04", "planting", "keisha.brown@example.com", 1], ["2027-09-04", "planting", "maya.thompson@example.com", 1], ["2027-09-04", "planting", "maya.thompson@example.com", 2], ["2027-09-11", "composting", "isaac.cohen@example.com", 1.5], ["2027-09-11", "planting", "keisha.brown@example.com", 1.5], ["2027-09-18", "planting", "dev.patel@example.com", 1.5], ["2027-09-18", "composting", "farah.haddad@example.com", 1], ["2027-09-18", "planting", "maya.thompson@example.com", 2], ["2027-09-18", "watering", "maya.thompson@example.com", 1], ["2027-09-25", "weeding", "ava.lopez@example.com", 2], ["2027-09-25", "planting", "elena.rossi@example.com", 1.5], ["2027-09-25", "weeding", "keisha.brown@example.com", 1.5], ["2027-09-25", "composting", "maya.thompson@example.com", 1.5]]}], "formats": [{"range": "A1:D1", "fontWeight": "bold"}, {"range": "A2:A84", "numberFormat": "@"}]}
{"sheetName": "Members", "rows": 16, "columns": 8, "data": [{"range": "A1:E13", "values": [["First Name", "Last Name", "Email", "Dues Paid", "Volunteer Hours"], ["Maya", "Thompson", "maya.thompson@example.com", true, 24], ["Ava", "Lopez", "ava.lopez@example.com", true, 12], ["Ben", "Okafor", "ben.okafor@example.com", false, 4], ["Cam", "Nguyen", "cam.nguyen@example.com", true, 9.5], ["Dev", "Patel", "dev.patel@example.com", true, 15], ["Elena", "Rossi", "elena.rossi@example.com", false, 6.5], ["Farah", "Haddad", "farah.haddad@example.com", true, 11], ["Gabe", "Martinez", "gabe.martinez@example.com", false, 2], ["Hana", "Kim", "hana.kim@example.com", true, 18.5], ["Isaac", "Cohen", "isaac.cohen@example.com", true, 7], ["Jordan", "Lee", "jordan.lee@example.com", false, 0], ["Keisha", "Brown", "keisha.brown@example.com", true, 13.5]]}], "formats": [{"range": "A1:E1", "fontWeight": "bold"}]}
function testLogShiftEmailsForDate() {
  logShiftEmailsForDate("2027-04-10")
}

// Looks through the Members data for a matching email and returns the first name
// Returns "" if no match is found
function findMemberFirstName(email, membersData) {
  let firstName = ""

  for (let i = 1; i < membersData.length; i++) {
    const memberEmail = membersData[i][2]  // column C

    if (memberEmail === email) {
      firstName = membersData[i][0]  // column A
    }
  }

  return firstName
}

// Finds every shift on the given date and logs the email that would be sent
function logShiftEmailsForDate(dateText) {
  const shiftsSheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Shifts")
  const shiftsData = shiftsSheet.getDataRange().getValues()

  const membersSheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Members")
  const membersData = membersSheet.getDataRange().getValues()

  for (let i = 1; i < shiftsData.length; i++) {
    const shiftDate = shiftsData[i][0]

    if (shiftDate === dateText) {
      const task = shiftsData[i][1]
      const email = shiftsData[i][2]
      const hours = shiftsData[i][3]

      const firstName = findMemberFirstName(email, membersData)

      const subject = `Reminder: your shift tomorrow`
      const body = `Hi ${firstName}, this is a reminder that you have a ${task} shift tomorrow (${dateText}) for ${hours} hours.`

      Logger.log(`To: ${email}`)
      Logger.log(`Subject: ${subject}`)
      Logger.log(`Body: ${body}`)
    }
  }
}

Read the logged emails as if you were the member receiving one. Farah's and Hana's say "for 1.5 hours," which reads fine. Dev's says "for 1 hours." Small details like this are exactly what a dry run is for: you see them before anyone else does. (Fixing it takes one if. Try it.)

When the logged emails look right, replace the three Logger.log lines with one call to MailApp.sendEmail(email, subject, body), test once with a date and your own address in place of the members', and then set up a weekly time-driven trigger for logSaturdayShiftEmails (you might rename it sendSaturdayShiftReminders at that point) on Fridays.

Dry run — Running code that would take an action, such as sending email, so that it only logs what it would do. It lets you check the results before anything happens for real.

14.4 Calendar Events

The club's workdays are Saturday mornings, and members keep asking when the next one is. Putting them on a shared calendar answers that. Here's a request for May's workdays, in a new chat with your learner profile:

Add an event to my Google Calendar for every Saturday in May 2027, from 9:00 to 11:00 in the morning, titled Garden Workday.send

This task needs two things that aren't on your list yet, so let me flag them first:

  1. CalendarApp — a service like SpreadsheetApp, but for Google Calendar instead of Sheets.
  2. new Date(year, month, day, hour, minute) — a way to build a specific date and time. The tricky part: months are numbered starting at 0, so January is 0 and May is 4.

Since there's no way to create calendar events without these, I'll use them, but keep it as simple as possible and explain each part.

I figured out that in May 2027, the Saturdays fall on the 1st, 8th, 15th, 22nd, and 29th, so I can just list those days instead of calculating them in code.

function addGardenWorkdays() {
  // Get your main Google Calendar
  const calendar = CalendarApp.getDefaultCalendar()

  // The days in May 2027 that are Saturdays
  const saturdays = [1, 8, 15, 22, 29]

  // Loop through each Saturday
  for (let i = 0; i < saturdays.length; i++) {
    // Get the day number for this loop
    const day = saturdays[i]

    // Build the start time: year 2027, month 4 (May), this day, 9:00
    const startTime = new Date(2027, 4, day, 9, 0)

    // Build the end time: same day, 11:00
    const endTime = new Date(2027, 4, day, 11, 0)

    // Create the event on the calendar
    calendar.createEvent("Garden Workday", startTime, endTime)
  }
}

How to run it: 1. Paste this into the Apps Script editor. 2. In the toolbar, choose addGardenWorkdays from the function dropdown. 3. Click Run. 4. The first time, Google will ask you to authorize access to your Calendar — approve it. 5. Check your Google Calendar for May 2027 to confirm the five events were added.

No trigger is needed here since you're just running it once to create the events.

Reply from Claude, captured September 26, 2026

Read. CalendarApp.getDefaultCalendar() gets your main calendar, and createEvent(title, start, end) adds an event, with the start and end as Date objects. The assistant flagged the month-counting trap, and the code uses 4 for May.

Look at how it found the Saturdays: it worked them out itself and typed them into an array, [1, 8, 15, 22, 29]. That's a fact you should check, because an assistant can get a calendar calculation wrong as easily as a person. You can check it right here:

const saturdays = [1, 8, 15, 22, 29]
for (let i = 0; i < saturdays.length; i++) {
  const date = new Date(2027, 4, saturdays[i])
  // getDay() is 6 for Saturday
  console.log(saturdays[i], date.getDay())
}

All five give 6, so the list is right. A version that finds the Saturdays itself, by starting at May 1 and adding 7 days until the month changes, would work for any month without anyone doing the calculation. It's a good exercise.

Two more things to check before you run it:

For a club, it's better to create a separate calendar for the garden and share it with members than to fill your own. CalendarApp.getCalendarsByName("Garden Workdays") finds a calendar by name. Your assistant can show you how to use it.

14.5 Your Learner Profile

The new rule builds the dry run into every request that sends or schedules something. You'll still decide when to switch to the real thing, and you'll do it after reading the output.

14.6 Summary

MailApp.sendEmail sends an email with an address, a subject and a body. Use it rather than GmailApp when sending is all you need, because GmailApp asks for full access to your Gmail. The permission screen is the final word on what a script can do, even when an assistant describes it confidently. Dates are Date objects: new Date() is now, months count from 0, getDate() is the day of the month and getDay() the day of the week, and setDate moves a date forward or back. Comparing dates stored as text is simplest when you turn the date you have into the same text form. Because email and calendar changes can't be undone, check them with a dry run that logs instead of acting, test with your own address, and read the code for anything that would repeat when run twice. Next, the club's scripts will write documents: certificates for volunteers and a weekly newsletter.