Google App Script to generate Calendar and Habit Tracker in Google Sheets.

Code.gs

// https://bit.ly/2021_habit_tracker

var monthName = [
  'January',
  'February',
  'March',
  'April',
  'May',
  'June',
  'July',
  'August',
  'September',
  'October',
  'November',
  'December',
  'January',
]

var configurationMap = {
"YEAR":       "B2",
"TIMEZONE":   "B3",
"THEME":      "B4",
"JANUARY":    "B5",
"FEBRUARY":   "B6",
"MARCH":      "B7",
"APRIL":      "B8",
"MAY":        "B9",
"JUNE":       "B10",
"JULY":       "B11",
"AUGUST":     "B12",
"SEPTEMBER":  "B13",
"OCTOBER":    "B14",
"NOVEMBER":   "B15",
"DECEMBER":   "B16",
}

var daysOfWeekArray = [[
  "S", "M", "T", "W" ,"T", "F" , "S"
]]

const configurationSheet = SpreadsheetApp.getActive().getSheetByName('Configuration ⚙️');
const habitsSheet = SpreadsheetApp.getActive().getSheetByName('Habits ⛹🏻‍♂️');

const themeColor = String(configurationSheet.getRange(configurationMap["THEME"]).getBackground());
const timeZone = String(configurationSheet.getRange(configurationMap["TIMEZONE"]).getValue());

const startColumn = "A"
const endColumn = "AN"
const totalColumn = "AO"

function authorize(){
  var user = Session.getActiveUser().getEmail();
  var userProperties = PropertiesService.getUserProperties();
  userProperties.setProperty('AuthTo', user);
  var msg = "Hi, " + user + "\nYou are now authorized."
  SpreadsheetApp.getUi().alert(msg);
}

function getCalendarSheet() {
  var calendarSheet = SpreadsheetApp.getActive().getSheetByName('Calendar 📆');
  if (calendarSheet === null) {
    calendarSheet = SpreadsheetApp.getActive().insertSheet('Calendar 📆');
  }
  return calendarSheet;
}

function getHabits() {
  var lastRow = habitsSheet.getRange("A:A").getValues().filter(String).length + 1;
  var habits = habitsSheet.getRange("A2:A" + lastRow).getValues();
  return habits;
}

function getCalendarYear(){
  var year = Number(configurationSheet.getRange(configurationMap["YEAR"]).getValue());
  if (year < 2020 || year > 2100){
    var currentYear = Number(Utilities.formatDate(new Date(), timeZone, "yyyy"));
    year = currentYear;
  }
  return year;
}

function getEmoji(monthName) {
  var emoji = configurationSheet.getRange(configurationMap[monthName.toUpperCase()]).getDisplayValue();
  return emoji || "☃️";
}

function clearCalendar() {
    var sheet = getCalendarSheet();
    sheet.getRange(startColumn + ":" + totalColumn).clearDataValidations().clearFormat().clearContent().clearNote().clear();
    sheet.setColumnWidths(1, 8, 25)
    sheet.setColumnWidths(9, 1, 150);
    sheet.setColumnWidths(10, 31, 25);
    sheet.setColumnWidths(41, 1, 100);
}

function displayMonthCalendar(sheet, theme, habits, startRow, monthIndex, monthName, year, startDate, startDay, endDate){
  console.log(monthIndex, monthName, year, startDate, startDay, endDate);
  var daysOfWeekRow = startRow + 2;
  var datesOfMonthRow = daysOfWeekRow + 1;

  // Display Days
  sheet.getRange("A" + startRow).setValue(getEmoji(monthName));
  sheet.getRange("A" + startRow + ":H" + startRow).setFontFamily("Century Gothic")
        .setFontSize(10)
        .setFontColor("black")
        .setBackground(theme)
        .setHorizontalAlignment("center");
  sheet.getRange("B" + startRow).setValue(monthName + " - " + year).setFontWeight("bold");
  sheet.getRange("B" + startRow + ":H" + startRow).merge();
  sheet.getRange("B" + daysOfWeekRow + ":H" + daysOfWeekRow).setValues(daysOfWeekArray)
        .setFontWeight("bold")
        .setFontFamily("Century Gothic")
        .setFontSize(10)
        .setFontColor("black")
        .setHorizontalAlignment("center");
  
  // Display Dates
  var dateColumn = startDay + 2;
  for (var dateIndex = startDate; dateIndex <= endDate; dateIndex++) {
    sheet.getRange(datesOfMonthRow, dateColumn).setValue(dateIndex)
        .setNumberFormat("#")
        .setFontFamily("Century Gothic")
        .setFontSize(10)
        .setFontColor("black")
        .setHorizontalAlignment("center");
    if (dateColumn++ === 8) {
      datesOfMonthRow = datesOfMonthRow + 1;
      dateColumn = 2;
    }
  }
} 

function displayMonthBreakdown(sheet, theme, habits, startRow, monthIndex, monthName, year, startDate, startDay, endDate){
  // console.log(sheet, monthIndex, monthName, year, startDate, startDay, endDate);
  var habitsColumn = "I"
  var totalColumn = 41
  var startDatesColumn = 10
  var datesOfMonthRow = startRow + 1;
  var checkBoxStartRow = datesOfMonthRow + 1;
  var date = 0;
  var datesArray = [Array(endDate)];
  var i = 0;
  var day = startDay;
  var daysArray = [Array(endDate)];

  while(date<endDate) datesArray[0][date++]=date;
  while(i<endDate){
    daysArray[0][i++]=daysOfWeekArray[0][day++ % 6];
    if(day === 7){
      day = 0;
    }
  }

  // Display Habits Row I - Dates
  sheet.getRange(habitsColumn + startRow + ":AO" + startRow)
        .setFontWeight("bold")
        .setFontFamily("Century Gothic")
        .setFontSize(10)
        .setFontColor("black")
        .setBackground(theme)
        .setHorizontalAlignment("center");
  sheet.getRange(habitsColumn + startRow).setValue("Habits");
  sheet.getRange(startRow, startDatesColumn, 1, endDate).setValues(datesArray);
  sheet.getRange(startRow, totalColumn).setValue("Total");

  // Display Habits Row II - Days
  sheet.getRange(datesOfMonthRow, startDatesColumn, 1, endDate).setValues(daysArray)
        .setFontWeight("bold")
        .setFontFamily("Century Gothic")
        .setFontSize(10)
        .setFontColor("black")
        .setBackground(theme)
        .setHorizontalAlignment("center");

  // Display Habits Columns - Habits Array
  var query = "=ARRAYFORMULA('Habits ⛹🏻‍♂️'!A2:A" + habits.length + ")";
  sheet.getRange(checkBoxStartRow, startDatesColumn -1).setFormula(query);
  sheet.getRange(checkBoxStartRow, startDatesColumn - 1, habits.length, 1)
        .setFontWeight("bold")
        .setFontFamily("Century Gothic")
        .setFontSize(10)
        .setFontColor("black")
        .setHorizontalAlignment("center");  

  // Display Habits Rows - Checkboxes
  sheet.getRange(checkBoxStartRow, startDatesColumn, habits.length - 1, endDate).insertCheckboxes()
        .setHorizontalAlignment("center");

  // Display Habits Rows - Checkboxes
  for (var x=checkBoxStartRow; x < checkBoxStartRow + habits.length - 1; x++) {
    var totalDoneFormula = "=COUNTIF(J"+x+":AN"+x+", TRUE)";
    sheet.getRange(x, totalColumn).setFormula(totalDoneFormula);
  }
}

function buildHabitTracker() {
  clearCalendar()
  var sheet = getCalendarSheet();

  var habits = getHabits()
  var year = getCalendarYear()
  var defaultStartDate = 1;

  
  var previousMonth = monthName[0];
  var startDateString = previousMonth + ' ' + defaultStartDate + ', '+ year;
  var currentMonthStart = new Date(startDateString)
  var startDate = new Date(currentMonthStart.setDate(1));
  var startRow = 0;
  var interval = 1;

  for (var monthIndex = 1; monthIndex <= 12; monthIndex++) {
    var currentMonthFullName = monthName[monthIndex];
    var endDateString = currentMonthFullName + ' ' + defaultStartDate + ', '+ year;
    var currentMonthEnd = new Date(endDateString);
    var endDate = new Date(currentMonthEnd.setDate(0));
    var startRow = startRow + interval;
  
    displayMonthCalendar(
      sheet, 
      themeColor,
      habits,
      startRow,
      monthIndex - 1, 
      previousMonth, 
      year,
      1,
      Number(startDate.getDay()),
      Number(endDate.getDate())
    );
  
    displayMonthBreakdown(
      sheet, 
      themeColor,
      habits,
      startRow,
      monthIndex - 1, 
      previousMonth, 
      year,
      1,
      Number(startDate.getDay()),
      Number(endDate.getDate())
    );

    previousMonth = currentMonthFullName;
    var startDateString = previousMonth + ' ' + defaultStartDate + ', '+ year;
    var currentMonthStart = new Date(startDateString)
    var startDate = new Date(currentMonthStart.setDate(1));
    
    var interval = habits.length + 3;
    console.log("\n==============================\n")
  }
}

function onOpen() {
    var ui = SpreadsheetApp.getUi();
    ui.createMenu('Habit Tracker ⛳️')
      .addItem('Authorize ✍🏻', 'authorize')
      .addSeparator()
      .addItem('Build Habit Tracker 🎬', 'buildHabitTracker')
      .addItem('Clear Calendar 🆑', 'clearCalendar')
      .addToUi();
}

2021 Habit Tracker

Introducing the habit tracker that can be used for the entire lifetime. Just configure the year annually and you are good to go to be able to track your new habits every year. You may feel free to change the code or keep a record of your habits.

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