Colour Old Events - Google Apps Script

A Google Apps Script that automatically colours calendar events that occurred before a specified date. Perfect for visually organizing your calendar by dimming old events with a consistent color.

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Features

• 🎨 Automatic Event Coloring - Colors events older than your specified cutoff date
• 📅 Multiple Calendar Support - Process events across multiple calendars
• ⚙️ Flexible Configuration - Customizable date ranges and event types
• 🔄 Daily Automation - Set up triggers to run automatically
• 🎯 Event Type Filtering - Choose which types of events to color
• 🚀 Efficient Processing - Handles large numbers of events with pagination

Quick Start

1. Copy the Script

   • Go to Google Apps Script
   • Create a new project
   • Replace the default code with the contents of Code.js

2. Enable Calendar API

   • In Apps Script, click "Services" in the left sidebar
   • Click "+ Add a service"
   • Select "Google Calendar API" and click "Add"

3. Configure Settings

   • Edit the configuration section at the top of the script
   • Add your calendar IDs to the CALENDAR_IDS array
   • Adjust other settings as needed (see Configuration section below)

4. Set Up Automation

   • Click "Triggers" in the left sidebar
   • Click "+ Add Trigger"
   • Choose function: ColorOldEvents
   • Event source: Time-driven
   • Type: Day timer
   • Time of day: Choose your preferred time

Configuration

Calendar IDs

const CALENDAR_IDS = [
  'primary',                           // Your main calendar
  'example@group.calendar.google.com', // Shared calendar
  'another@group.calendar.google.com'  // Another calendar
];

How to find Calendar IDs:

• Go to Google Calendar settings
• Click on the calendar you want to include
• Scroll down to "Calendar ID"
• For your primary calendar, use 'primary'

Date Settings

const DATE_OFFSET_DAYS = -1;        // -1 = yesterday and everything earlier
const PROCESSING_RANGE_DAYS = 30;   // Look back 30 days from the cutoff

Event Color

const EVENT_COLOR = '8'; // Graphite (grey)

Available Colors:

• '0': Default
• '1': Lavender
• '2': Sage
• '3': Grape
• '4': Flamingo
• '5': Banana
• '6': Tangerine
• '7': Peacock
• '8': Graphite (recommended for old events)
• '9': Blueberry
• '10': Basil
• '11': Tomato

Event Types

const EVENT_TYPES = ['default']; // Only regular events

Available Event Types:

• 'default': Regular events
• 'birthday': Special all-day events with annual recurrence
• 'focusTime': Focus time events
• 'fromGmail': Events from Gmail
• 'outOfOffice': Out of office events
• 'workingLocation': Working location events

How It Works

1. Date Calculation: Determines the cutoff date based on your offset setting
2. Calendar Processing: Iterates through each configured calendar
3. Event Retrieval: Fetches events within the specified date range using the Google Calendar API
4. Filtering: Only processes events that match your criteria (event type, not already colored)
5. Color Application: Updates event colors using the Calendar API
6. Progress Logging: Provides detailed console output for monitoring

Example Use Cases

• Archive Old Events: Color all events older than yesterday with grey
• Seasonal Organization: Color events from last month with a specific color
• Event Type Management: Only color regular events, ignore birthdays
• Multiple Calendar Sync: Keep consistent coloring across work and personal calendars

Troubleshooting

Common Issues

"No calendar IDs configured" error

• Make sure you've added at least one calendar ID to the CALENDAR_IDS array

Permission errors

• Ensure the Google Calendar API is enabled in your Apps Script project
• Check that you have edit permissions for the calendars you're trying to modify

Script timeout

• For large numbers of events, the script includes delays to respect API limits
• Consider reducing the PROCESSING_RANGE_DAYS for initial runs

Monitoring

The script provides detailed console logging. To view logs:

1. Run the script manually from the Apps Script editor
2. Click "Execution log" to see detailed output
3. Monitor daily runs through the "Executions" tab

Technical Details

• API Limits: Includes built-in rate limiting and error handling
• Pagination: Handles large result sets automatically
• OAuth Scopes: Requires calendar.events permission
• Date Format: Uses RFC3339 format for API calls
• Event Processing: Client-side filtering for event types and colors

Contributing

This is a standalone script designed to be copied and customized. Feel free to:

• Modify the configuration for your needs
• Add additional filtering logic
• Extend the color selection options
• Add more comprehensive error handling

License

This script is provided as-is for educational and personal use. Modify and distribute as needed.