@natlibfi/issn-verify/README.md

Verify ISSN (International Standard Serial Number)

# issn-verify [![NPM Version](https://img.shields.io/npm/v/@natlibfi/issn-verify.svg)](https://npmjs.org/package/@natlibfi/issn-verify)

**This software is fork of https://github.com/malantonio/issn-verify with updated dependencies**

checks if an issn number is valid with regex and by confirming the check digit. regex and algorithm via [http://en.wikipedia.org/wiki/International\_Standard\_Serial\_Number](http://en.wikipedia.org/wiki/International_Standard_Serial_Number)

## usage

### via node/io.js

```javascript
var issn = require('issn-verify');
var test = "0000-000X";

if ( issn(test) ) {
    // do something with a valid issn
} else {
    // do something with an invalid issn
}
```

### in html
```html
<script src="/path/to/issnVerify.js"></script>
<script>
    var input = document.getElementById('issn')
      , issn = null
      ;

    input.addEventListener('blur', function(e) {
        issn = e.target.value;
        if ( issn && !issnVerify(issn) ) {
            // do something
        }
    });
</script>
```

## License and copyright
**This software is fork of https://github.com/malantonio/issn-verify with updated dependencies**

Copyright (c) 2018, 2023-2026 **University Of Helsinki (The National Library Of Finland)**

This project's source code is licensed under the terms of **MIT License** or any later version.