PATTENS Email Tools

PATTENS Email Tools is a browser-based toolkit for working with email lists, email HTML, and campaign assets.

Three tools, one page:

• Email Validator — syntax‑check and deduplicate email addresses
• Dynamics Email Converter — prepare third‑party HTML for Dynamics 365 Customer Insights – Journeys
• Generate — create campaign names, tracked URLs, and encoded survey links

Everything runs locally in your browser — no server, no account, no data leaving your machine.

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Email Validator

Check email addresses before adding them to a campaign, CRM, or import file.

You can:

• Paste email addresses directly into the page
• Upload a CSV file
• Check emails copied from spreadsheets or contact exports
• See how many emails were found
• See how many emails are valid
• See how many emails are invalid
• See duplicate email addresses
• View a full per‑email report
• Download the validation report as a CSV
• Clear the tool and start again

Limits

• CSV uploads up to 5 MB
• Up to 300 email entries at a time

What It Checks

The validator checks whether email addresses look correctly formatted. It flags:

• Missing @
• Invalid domain format
• Duplicate addresses (case‑insensitive)
• Consecutive dots
• Invalid characters
• Overly long email addresses

It does not guarantee that an inbox exists or that a message will be delivered.

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Dynamics Email Converter

Adapt third‑party email HTML into Dynamics 365 Customer Insights – Journeys compatible markup.

You can:

• Paste original email HTML
• Convert text, images, and buttons into Dynamics‑ready blocks
• Preview the original and converted email side‑by‑side
• Copy the converted HTML
• Refresh previews after making manual edits
• See a conversion summary
• Review warnings when the source HTML may need manual attention

Limits

• Converter input up to 500 KB of HTML

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Generate

Create consistent marketing assets:

• Campaign names — Business, year, region, descriptor, sales play, and language joined with hyphens
• Tracked URLs — Base URL with UTM‑style parameters (source, medium, campaign, content, term, CRM campaign)
• Survey URLs — Encoded CRM context appended to base survey links

Generated items persist in your browser's localStorage and are restored when you revisit the page.

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One Page, Three Tools

The main page includes a navigation bar to switch between tools:

Tool	Shortcut
Generate	Default view
Convert	Dynamics email converter
Validate	Email validator

Switch between them without leaving the page.

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Privacy

All processing happens client‑side in your browser. Email addresses, pasted HTML, and generated items are handled locally. No data is sent to any server.

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Development

Project Structure

├── index.html              # Single‑page app shell (Tailwind‑styled, imports all tools)
├── src/
│   ├── validator/
│   │   └── validator.js    # Email validation logic (Pattens.validator)
│   ├── app.js              # Dynamics email converter (Pattens.converter)
│   └── generate.js         # Campaign/link/survey generator (Pattens.generator)
├── __tests__/              # Jest tests (mirror src/ structure)
│   ├── app.test.js         # Converter tests
│   ├── generator.test.js   # Generator tests
│   └── validator.test.js   # Validator tests (loads real source)
├── test-fixtures/          # CSV and HTML fixture files for tests
├── docs/                   # Conversion rules, Dynamics attribute docs
├── skills/                 # Agent skill definitions
├── assets/                 # Static assets (SVG logos, etc.)
├── .github/
│   └── copilot-instructions.md  # Copilot coding guidelines
├── package.json
└── README.md

Running Locally

Start a local development server:

npm run dev

Then open http://localhost:3001 in your browser.

Running Tests

The project uses Jest with jsdom for automated testing:

npm test              # run all tests once
npm run test:watch    # run tests in watch mode
npm run test:coverage # run tests with coverage report

Test Suites

Suite	What it covers
__tests__/app.test.js	HTML parsing, block analysis, Dynamics conversion, output validation, utility functions
__tests__/generator.test.js	Campaign code building, tracked link generation, survey URL construction, localStorage persistence
__tests__/validator.test.js	Email syntax checking, CSV parsing, duplicate detection, sanitization, summary calculations

Tests load the real source files via fs.readFileSync + (0, eval)(code) — no function copies are used.

Reliability Features

• Debounced previews — Textarea input is debounced (300 ms) so typing large HTML doesn't freeze the browser
• DOMParser error detection — Malformed HTML that produces a parser error is caught and reported
• Exception‑safe DOM walks — Temporary attributes are always cleaned up even if the walker throws
• Pipeline error boundaries — Each conversion stage fails independently; earlier results are preserved
• Input size limits — Converter rejects HTML over 500 KB; validator rejects files over 5 MB
• Namespaced APIs — All modules live under window.Pattens.{module} to avoid global collisions
• Resilient sample loading — Sample HTML files load with a root‑relative path and a local fallback
• Safe iframe sandboxes — Preview iframes use sandbox="allow-same-origin" for consistent rendering

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License

This project is free for personal, educational, research, hobby, and other non-commercial use only. Commercial use requires prior written permission from the copyright holder.

See the LICENSE file for the complete terms.

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Credits

Copyright Mylo Kaye 2026.

Built by Mylo Kaye with AI.