callsign.js

This JavaScript library gives website users more ways to interact with written ITU call signs, including for amateur radio.

Demo

See a live example at https://phieri.github.io/callsign.js/

Usage

Upload callsign.js and callsign.css to your web server and include the script on the page. The library creates a shadow root for each rendered call sign and injects the stylesheet automatically unless you override it with data-css-path.

<script id="callsign-js" src="callsign.js" defer></script>

Tag the call signs with the custom HTML tag <call-sign>:

<p>I had contact with <call-sign>SM8AYA</call-sign> on shortwave.</p>

Options

Options can be set as attributes in the <script> tag.

Name	Default	Description
data-flag	true	Show a country flag before the call sign.
data-monospace	true	Render the call sign with a monospace font.
data-phonetic	true	Add phonetic information for screen readers and tooltips.
data-search	false	Find and mark up untagged call signs in the document.
data-css-path	callsign.css	Path to the stylesheet that the library injects into each shadow root.

Customization

You can customize the appearance by overriding the CSS custom properties on the <call-sign> host element. These values flow into the shadow DOM that wraps each rendered call sign:

call-sign {
  --cs-border-color: #007acc;
  --cs-background-color: #e0f0ff;
  --cs-border-radius: 5px;
}

Testing

The project uses Jest for unit tests, ESLint for code quality checks, and manual browser validation for the rendered shadow-DOM output.

Running Tests

# Install dependencies
npm install

# Run all tests
npm test

# Run linting
npm run lint

Test Coverage

The current suite covers the library's core behavior in browser-like conditions:

• call sign parsing and validation
• country prefix lookups and flag generation
• phonetic expansion
• auto-detection of untagged call signs in text content

The test files are located in the tests/ directory.

Minification

The files are intentionally not provided minified. Amateur radio is about learning and experimenting. Minified files makes it drastically harder to understand the code.

References

ITU Prefix Table Data Sources

The PREFIX_TABLE mapping in this library is compiled from multiple authoritative sources to ensure accuracy across all 160 countries:

• ITU Radio Regulations Appendix 42 – Table of allocation of international call sign series - Official ITU allocation table
• ITU Radiocommunication Bureau Circular - Current call sign assignments and updates
• ARRL International Call Sign Series - Comprehensive amateur radio call sign reference
• ITU Master International Frequency Register (MIFR) - Official frequency and call sign database
• Country-specific amateur radio licensing authorities - National regulatory bodies via IARU member societies
• Radio-Electronics.com Call Sign Database - Cross-reference for prefix verification

General References

• ITU Radio Regulations Article 19 – Identification of stations
• ITU prefix – Wikipedia
• International Amateur Radio Union (IARU) - Global amateur radio coordination