Google Apps Script

Google Apps Script

Overview

Cloud-based JavaScript platform for automating Google Workspace services. Server-side V8 runtime with automatic OAuth integration across Sheets, Docs, Gmail, Drive, Calendar, and more.

When to Use This Skill

Invoke this skill when:

• Automating Google Sheets operations (reading, writing, formatting)
• Creating or editing Google Docs programmatically
• Managing Gmail messages and sending emails
• Working with Google Drive files and folders
• Automating Google Calendar events
• Implementing triggers (time-based or event-based)
• Building custom functions for Sheets
• Creating Google Workspace add-ons
• Handling OAuth scopes and authorisation
• Making HTTP requests to external APIs with UrlFetchApp
• Using persistent storage with PropertiesService
• Implementing caching strategies with CacheService
• Optimising performance with batch operations
• Debugging Apps Script code or authorisation issues

Core Services

1. SpreadsheetApp - Google Sheets automation (read, write, format, data validation)
2. DocumentApp - Google Docs creation and editing
3. GmailApp & MailApp - Email operations (send, search, manage labels)
4. DriveApp - File and folder management, sharing, permissions
5. CalendarApp - Calendar events, recurring appointments, reminders
6. Triggers & ScriptApp - Time-based and event-driven automation

Quick Start

function generateWeeklyReport() {
  const ss = SpreadsheetApp.getActiveSpreadsheet();
  const sheet = ss.getSheetByName('Data');
  const data = sheet.getRange('A2:D').getValues();

  const report = data.filter(row => row[0]);
  const summarySheet = ss.getSheetByName('Summary') || ss.insertSheet('Summary');
  summarySheet.clear();
  summarySheet.appendRow(['Name', 'Value', 'Status']);
  report.forEach(row => summarySheet.appendRow([row[0], row[1], row[2]]));

  MailApp.sendEmail({
    to: Session.getEffectiveUser().getEmail(),
    subject: 'Weekly Report Generated',
    body: `Report generated with ${report.length} records.`
  });
}

Best Practices

• Batch operations - read/write ranges in bulk, never cell-by-cell in loops
• Cache data - use CacheService (25 min TTL) for frequently accessed data
• Error handling - wrap operations in try/catch, log errors to a sheet for audit trails
• Respect limits - 6-minute execution timeout; split large jobs across triggers
• Minimise scopes - request only necessary OAuth permissions in appscript.json
• Persistent storage - use PropertiesService for configuration and state
• Validate inputs - always check objects exist before accessing properties

See references/best-practices.md for detailed examples of each practice.

Validation & Testing

Use the validation scripts in scripts/ for pre-deployment checks:

• scripts/validators.py - Validate spreadsheet operations, range notations, and data structures

Debug with Logger.log() and view output via View > Logs (Cmd/Ctrl + Enter). Use breakpoints in the Apps Script editor for step-through debugging.

Integration with Other Skills

• google-ads-scripts - Export Google Ads data to Sheets for reporting
• gtm-datalayer - Coordinate with GTM for tracking events triggered by Apps Script
• ga4-bigquery - Query BigQuery from Apps Script and write results to Sheets

Troubleshooting

References

Detailed content is available in reference files (loaded on demand):

• references/apps-script-api-reference.md - Complete API reference for all built-in services, triggers, authorisation, and performance optimisation
• references/examples.md - Production-ready code examples (spreadsheet reports, Gmail auto-responder, document generation, trigger setup)
• references/best-practices.md - Detailed best practices with code blocks for batch operations, caching, error handling, scopes, and persistence
• references/patterns.md - Common reusable patterns (data validation, retry logic, form response processing)